Canceling AT&T Business internet is not one phone call. It is a sequence. The call is the last step, not the first.
Most of the money people lose comes from doing the steps in the wrong order. They cancel before the number port finishes. They call three days into a new billing cycle. They accept the early termination fee the rep quotes without checking if they owe it at all. You are protecting three things, in this order: your phone numbers, your final bill, and your refusal to pay a fee you already satisfied.
Know which AT&T product you have
Pull your order confirmation or Business Service Agreement before you touch the phone. The terms differ a lot.
AT&T Business Fiber and Internet for Business run on a promotional term. After that term you are month to month, and the early termination fee prorates down each month. AT&T Dedicated Internet is different. It runs on a 36-month term, and the fee is a percentage of your remaining monthly charges. Find the term start date, the term length, and the clause called "Early Termination Fee" or "Termination Charges" by name.
Check whether you owe a fee at all
The fee is not fixed. Reps quote the default figure anyway, even when your term already expired. So do the math yourself.
For fiber, the fee prorates. Say your promo term was 24 months and you are at month 20. Four months remain, so the fee is small, and many accounts are past the term with zero fee. For Dedicated Internet, take the percentage in your agreement times your monthly charge times the months left in the 36.
Some situations waive the fee. AT&T raised your price mid-term and your agreement lets you leave within 30 days of the notice. You moved outside the AT&T footprint. You have a documented outage history. Or a new tenant takes over through an Assumption of Billing Responsibility. Ask the rep for the exact fee dollar figure and the term end date. Write both down with the rep's name and the call reference number.
Port your numbers first
The new carrier starts the port. AT&T does not. And if you cancel the internet first, you can drop the port and lose the numbers for good. This is the mistake that hurts most.
You need the account number, the account passcode or PIN, the authorized contact name, and the billing address exactly as AT&T has it. Request a Customer Service Record to confirm the numbers and billing details match. Porting takes 1 to 10 business days, depending on how many lines you have. Cancel the internet only after the numbers are live on the new carrier.
Time the cancellation to the billing cycle
AT&T does not prorate the final bill on business broadband. Service runs to the end of the current cycle no matter when you call. So timing is worth up to a full month.
Find the bill cycle date on your invoice. Schedule the disconnect for the last day of that cycle. Ask for a future-dated disconnect order, not an immediate one. A scheduled date also lets your new install overlap with no gap in service.
The call: what to say, what to get
Call AT&T Business at 800-321-2000. Say "disconnect service." Do not say "I'm thinking of leaving." That routes you to retention. Decline the offers unless you are actually open to staying.
Before you hang up, get four things. The disconnect order number. The effective disconnect date. The quoted fee, or "zero ETF" stated out loud. And confirmation that autopay stops after the final bill. Ask for it all by email. If you have voice, wireless, or TV on the account, name each one on the disconnect order. Anything you miss stays active.
Return the equipment and keep the receipt
Return the gateway within 21 days of disconnect through the AT&T UPS or FedEx process. Miss the window and the non-return charge runs about $150 per device. It shows up as an equipment fee on your final bill.
Photograph the serial numbers before you ship. Keep the drop-off receipt with the tracking number. That receipt is your proof if the fee lands anyway.
Audit the final bill
The final bill arrives 30 to 60 days after disconnect. Read it as a document to check, not a bill to pay.
Look for a fee that does not match what was quoted. A fee that appears when the term had expired. A non-return charge after you returned the gear. Charges past the disconnect date. A full month billed when you future-dated the disconnect right. Dispute by phone with the disconnect order number and call reference. Then in writing to AT&T Business billing disputes if they do not credit it. Cancel autopay at your bank only after the final bill is paid and correct.
Stop treating this as a phone call. Pull the agreement first. The fee is often smaller than quoted, or already zero.