Verizon charge me $800 because T-mobile didn't pay

I hate it when I hear stories like these because people should never be allowed to leave the store without understanding the exact sequence of events that need to happen, in what order and who’s responsible for doing what.

1. The customer pays of the balance on their phones.
2. The customer requests any devices that are SIM-locked be unlocked.
3. The customer verifies the unlocked status of their phones.
4. The customer contacts T-Mobile (in store or by phone) and initiates the porting process.
5. The customer obtains their final invoice from the old carrier and submits a copy of it to T-Mobile online.
6. T-Mobile verifies the invoice and that the phones in question are now used on new T-Mobile service.
7. T-Mobile sends the customer a prepaid (virtual?) MasterCard for the program amount.
8. The customer uses the prepaid card any way they like.

I’m sorry I can’t do anything about the situation, I’m just a customer, not an employee.