Invoice for Device Payout

I have spent the last 2 hours trying to get an Xfinity Agent to provide me with an invoice showing the exact amount left to pay on two devices. After speaking with 9 representatives, I still do not have this information. I do not need my monthly bill--it does not show the full payoff amount of the devices. As I have left Xfinity because of this kind of terrible customer service, I do not have full access to the billing page either. PLEASE can someone help me?!?!?!?1