What to Do When a Customer Texts STOP (and What It Costs If You Do Not)

A customer just replied STOP to your business number. Maybe it was a regular customer, maybe a new lead, maybe someone who meant to type "stop by later". Whatever the reason, what you do next matters: ignoring an opt-out is one of the fastest ways to get a business number blocked, and in the United States it can cost far more than that.

What STOP actually means

When someone replies STOP, they are withdrawing permission to receive texts from you. That is not a preference you can weigh against your sales targets. It is a clear instruction, and every rule that applies to business texting treats it that way.

STOP is not the only word. The industry standard set of opt-out keywords, which carriers recognise, includes:

• STOP, STOP ALL, STOPALL
• UNSUBSCRIBE
• CANCEL
• END
• QUIT
• and, more and more, plain phrases like OPT OUT and REVOKE

The keyword has to be the whole message. "Can you stop by at 3?" is a normal conversation. "Stop" on its own is an opt-out.

What happens automatically when someone texts STOP

On Twilio and Telnyx, the carrier steps in for you:

1. The carrier recognises the keyword.

   Standard opt-out words are caught before your software even sees the message.

2. It sends one confirmation.

   The customer gets a single message confirming they are unsubscribed. That is the only message they should get from that number until they opt back in.

3. It blocks that number.

   Further texts from the number they replied to are refused at the carrier. On Twilio, a send attempt fails with an opt-out error.

That sounds complete, but there is a gap most businesses miss: the carrier block only covers the one number they replied to. If you have a second business number, a sales line, a support line or a number in another state, nothing at the carrier stops a teammate, an automation or an AI from texting them from there. To the customer, that looks exactly like ignoring their STOP.

What you should do (and not do)

Do

• Stop on every number. Treat STOP as "stop texting me", not "stop texting me from this one line".
• Stop every sender. Your team, AI replies, appointment reminders, missed-call texts and phone menu texts all count.
• Record it. Note who opted out and when, so a new teammate does not text them next month.
• Make it easy to come back. They can text START. If they ask you to start again by phone or email, tell them how.

Do not

• Do not reply. No "are you sure?", no discount, no "we'll miss you". The carrier's confirmation is the last word.
• Do not switch numbers. Texting them from a different number to get round a block is exactly what carriers and regulators look for.
• Do not re-import them. An opted-out customer who reappears in a list you upload is still opted out.
• Do not argue with an accidental STOP. Call them instead.

Why it matters: carriers and the law

Carriers. Every business number in the US that texts customers is expected to honour opt-outs. Carriers watch opt-out rates; a rising number of STOPs is one of the signals that gets messages filtered or a number suspended. Your A2P 10DLC registration itself describes how people opt out, and breaking that promise puts the registration at risk. If you have ever had a number suspended, you know how disruptive that is.

The law. In the United States, business texting falls under the Telephone Consumer Protection Act (TCPA). People who receive texts they did not agree to, or texts after they opted out, can sue, and the law sets damages of $500 per text, up to $1,500 per text if the sender acted wilfully. A few dozen texts to the wrong person adds up fast, which is why opt-out mistakes are so attractive to lawyers. The FCC has also made clear that people can withdraw consent in any reasonable way, not just by texting a keyword, so "please stop texting me" in a normal message, or a request by phone or email, should be honoured too.

This is general information, not legal advice. If you text customers at any scale, it is worth a conversation with a lawyer who knows the TCPA and your state's rules.

The multi-number problem

Most small businesses that grow end up with more than one texting number: a main line, a second location, a sales number, a number in a new area code. That is where opt-out handling usually breaks.

The carrier keeps its block per number. Your team thinks in people. So the safe rule is simple: an opt-out belongs to the person, not the number. Whatever tool you use should apply one STOP to every number you own.

AI and automations make it more important, not less

If an AI answers your texts, or you send automatic reminders, the risk shifts from "a teammate forgot" to "the system did it a thousand times". Check that:

• your AI never replies to a STOP message (a reply to STOP is a text to someone who just withdrew consent);
• your AI and automations check the opt-out list before every send, on every number;
• a plain "yes" to a booking question is not mistaken for an opt-in, while START from an opted-out customer is.

Our comparison of ways to add an AI receptionist is a good place to see how much control each option gives you over this.

How TelBuddy handles STOP

TelBuddy runs on the Twilio or Telnyx account you already have, and handles opt-outs the way this guide recommends, on both carriers:

• Every opt-out word is recorded the moment it arrives: STOP, UNSUBSCRIBE, CANCEL, END, QUIT, OPT OUT and the rest.
• One STOP blocks every number. The person is blocked from all of your numbers, not just the one they replied to.
• Every sender checks first: your team in the inbox, AI replies, phone menu texts and missed-call texts. Your team sees a plain message instead of a carrier error.
• The AI never answers STOP or START, and a normal "yes" stays a normal reply.
• You can see it everywhere: an Opted out badge on the contact, a filter to list everyone who opted out, a note in the conversation, and the date in your contacts export.
• Requests by phone or email are covered too: mark the contact as opted out by hand and every text stops.
• START brings them back. Only the customer can undo an opt-out they texted, which is exactly how it should be.

The full details are in the STOP and opt-out guide, and the shared team inbox page shows how it fits with the rest of your texting.

A one-minute opt-out checklist

1. Do all your texting tools recognise STOP, UNSUBSCRIBE, CANCEL, END and QUIT?
2. Does one STOP block every number you text from?
3. Does your AI stay silent when someone texts STOP?
4. Do reminders and automations check the opt-out list before every send?
5. Can you see who opted out, and when?
6. Can you mark someone who asked by phone or email?
7. Do imported contacts keep their opt-out status?
8. Do you watch your opt-out rate and slow down when it rises?

If you answered no to any of these, that is your next fix. If you would rather have it handled for you, TelBuddy does all eight on your own Twilio or Telnyx number, and you can try it on the free trial.