Unable to pay our bill online for over 12 months

We've been having this issue for a full year. I had lost a bank card around that time and went to update and pay our bill with a new one when the trouble started.

Originally, we were told there was a glitch in the website and after being asked no less than twenty times by different reps to add my card information in various ways, we were then informed that we had "tried too many times" and that we were locked out of trying to add any sort of online payment method for six months. So we begrudgingly went to our local Xfinity store every month to pay our bill in cash. This went on the full year because even after the six months it still wouldn't allow any online payment, not even adding a payment method. My wife and I have made dozens of calls, and time after time, and promises of a resolution, it still isn't solved. I finally contacted Xfinity again recently after an enormous price hike and still being unable to pay online. The rep I spoke with was very patient and kind, and did her best to accommodate me, offering a $10 reduction via the connection of a bank account and automatic payments, so I have no problem with her. However, I went to pay my bill early and the Xfinity website and App gave me an error. 

This makes me nervous as it seems that even a bank connection might not be possible to pay our bill online. We have spent hours on the phone, speaking with people that promised a resolution but nothing has ever been done. 

We are tired, and another year of this is unacceptable, especially for the drastically increased price. I'm posting here in the hope that someone might have an answer, or that it catches the attention of someone who can elevate this. There is nothing else that my wife and I can do to rectify the situation.

Thank you for your time.