BYOD credit frustration

I have brought my own phone and paid off my installment. Now after submission, no matter what documents I upload, the system says it “invalid”. I even had submitted copy of my previous two months showing the installment amount, carrier and dates are all included.

it seems to me Xfinity is just buying some time so that it exceeds thirty days so that they don’t reimburse the customer.

Any comments are appreciated.