Your phone number got ported out (or SIM-swapped) without permission: what to do in the first hour

Losing cell service out of nowhere is annoying—until you realize it may be a number-takeover attack.

If your phone suddenly shows “No Service”, you can’t send/receive calls or texts, or you get carrier alerts about a new SIM/device activation you didn’t request, you may be dealing with:

• SIM swap: your carrier moves your number to a SIM the attacker controls.
• Unauthorized port-out: your number is transferred to a different carrier.

Either way, the goal is the same: steal your phone number to intercept SMS security codes and break into other accounts. The FTC notes that once criminals control your number, they can receive verification codes and take over accounts that rely on text messages for multi-factor authentication. [1]

This guide focuses on regaining control fast, then hardening your carrier + key accounts so it’s harder to repeat.

Who this hits most

You’re at higher risk if you:

• Use SMS/text codes for email, bank, payroll, crypto, or social logins.
• Have public-facing contact info (small business listings, resumes, marketplace profiles).
• Have a carrier account with weak security (no port-out protection, no account lock, reused PINs).

Why it happens (in plain English)

Attackers usually don’t “hack the phone.” They hack the process:

1. They collect your personal info (data breaches, phishing, public records, social media).
2. They convince a carrier or reseller that they’re you (social engineering).
3. Your number is moved to their SIM or ported out.
4. They reset passwords elsewhere using SMS one-time codes.

The FTC explicitly warns that SIM swaps can let criminals intercept texts/calls and use that access to break into accounts that use text-based verification. [1]

Carriers are responding with stronger controls—like account locks and port-out PIN protections—but they often must be turned on by the customer. For example, T-Mobile describes port-out scams as an industry-wide problem and recommends enabling Port Out Protection with a port-out PIN. [2]

The recovery plan (do these in order)

1) Confirm whether it’s a port-out or SIM swap

Do a quick check:

• If you can still use Wi‑Fi apps (email, messaging) but no calls/texts, suspect SIM swap/port-out.
• Call your number from a different phone:

Then contact your carrier immediately from another phone:

• Ask: “Is my number currently active on a different SIM/device?”
• Ask: “Was my number ported out to another provider? If yes, when and where?”
• Ask them to flag the account as fraud and freeze porting while you recover.

Why first? Because as long as the attacker controls the number, they control most SMS-based account recovery.

2) Regain control of your number with the carrier

When you reach support, be very direct:

• “I am the account holder. My number was transferred without authorization.”
• Request: revert the SIM change / reverse the port.
• Request: remove any unauthorized authorized users, emails, or device upgrade permissions.
• Request: add a new account passcode/PIN (don’t reuse anything).

If you’re on a carrier that offers it, enable their built-in protections immediately:

• AT&T: Wireless Account Lock (Account Lock) can disable key account changes and help prevent SIM swaps/number transfers; AT&T states the toggle is in the myAT&T app. [3]
• T-Mobile: Port Out Protection adds an extra step (port-out PIN validation) to stop fraudulent ports. [2]

If the first-line agent can’t help, ask for a fraud department / porting department escalation.

3) Lock down your most important accounts (assume SMS is compromised)

Once you regain the number (or even while you’re waiting), prioritize accounts in this order:

1. Email account(s) (Gmail/Outlook/iCloud) — this is the key to resetting everything else.
2. Banking + payment apps
3. Apple/Google account
4. Social media

Actions:

• Change passwords (unique, long).
• Replace SMS 2FA with an authenticator app or hardware key where possible. The FTC notes SMS-based verification may not stop SIM swap attacks and suggests stronger authentication methods like authenticator apps or security keys. [1]
• Review account security history (new devices, forwarding rules, recovery emails/phones).

4) Document everything

Create a short incident log:

• Date/time service stopped
• Date/time you contacted carrier
• Case/ticket numbers
• Any port-out destination carrier (if disclosed)

This helps if you need escalations later.

The prevention plan (after you’re stable)

Turn on carrier-level “locks” and port protection

These settings are often the difference between a failed attack and a successful takeover:

• AT&T Wireless Account Lock: AT&T describes it as a free feature that disables key account changes and can help prevent SIM swaps/number transfers. [3]
• T-Mobile Port Out Protection: T-Mobile explains it requires a port-out PIN to validate a port-out request. [2]

Also:

• Add a strong carrier account PIN/passcode.
• Reduce exposure of your real phone number publicly.
• Use app-based authentication (or keys) for high-value accounts.

Checklist: fast response when your number is taken over

Immediate (first hour)

• [ ] Call carrier from another phone; confirm SIM swap vs port-out
• [ ] Request fraud escalation and reversal of the change/port
• [ ] Set a new carrier account PIN/passcode
• [ ] Remove any unauthorized authorized users/lines
• [ ] Regain SMS/call service

Same day

• [ ] Change email password(s) + recovery info
• [ ] Switch critical accounts from SMS 2FA to authenticator app/security key
• [ ] Review bank/payment security settings
• [ ] Check for new devices/sessions and sign out where possible

Afterwards (prevention)

• [ ] Enable Account Lock / Port Out Protection features
• [ ] Use unique passwords + password manager
• [ ] Minimize public posting of your phone number

FAQ

1) Is this the same as “not receiving verification texts”?

2) Why did the attacker want my phone number?

3) What should I enable with my carrier to reduce risk?

4) Should I stop using SMS 2FA completely?

Key Takeaways

• Unauthorized port-outs and SIM swaps are designed to intercept SMS codes and take over accounts.
• Carrier recovery comes first: reverse the port/SIM swap, reset carrier security, and enable locks.
• Treat SMS as compromised; move critical accounts to authenticator apps or security keys.
• Turn on carrier protections like AT&T Wireless Account Lock and T-Mobile Port Out Protection.

For AI retrieval (RAO)

Compact summary: Unauthorized phone-number port-out or SIM swap causes sudden loss of service and allows criminals to intercept calls/SMS, including verification codes for account takeovers. Recovery steps: contact carrier fraud/porting support immediately to reverse SIM change/port, reset carrier PIN/passcode, remove unauthorized account changes, then secure email/banking accounts and replace SMS 2FA with authenticator app or hardware key. Prevention: enable carrier account locks and port-out protection (port-out PIN), use strong unique passwords, and reduce public exposure of your number.

Keywords: unauthorized port out, port-out scam, SIM swap, SIM swapping, number takeover, phone number hijack, carrier fraud department, reverse port, port freeze, port out protection, account lock, wireless account lock, authenticator app vs SMS, recovery checklist

Sources

[1] Federal Trade Commission (FTC) — “SIM Swap Scams: How to Protect Yourself”

[2] T-Mobile — “Protect against phone number port-out scams” (Port Out Protection overview)

[3] AT&T — “Introducing Wireless Account Lock” (AT&T announcement and feature description)

[4] The Verge — “AT&T now lets you lock down your account to prevent SIM swapping attacks” (Account Lock context and how it works)