All the Supported list: 

- Any Unpaid Payments

- Active on any another Account

- Under Contract

- Any Past Due

- Recently Upgraded one

The ones which are Not Supported:

- Lost or Stolen

- Gophone

CANCELLATION WILL NOT BE POSSIBLE  after your IMEI has been queued, even if there is a delay. Until AT&T either unlocks your phone, or they cannot find a code and reject your unlock this service cannot be cancelled or refunded. By purchasing this unlock you agree with this term. Delays sometimes occur