Blocked from adding new bank account, XFinity's fault not mine

Long time Xfinity customer here. On Autopay with Bank Account. I was a victim of bank fraud through check washing and had to close my bank account and open new one with new checks, routing and account number, etc. I only pay 2 bills in my life online, I am 58 years old. I write checks except for my ATT phone and my Xfinity which allow Autopay through my bank account and it gives you a little discount. I will NOT put it through a credit card under any circumstances so if somebody in authority does not rectify it quickly, I will quit Xfinity and get another provider. I am not an idiot, I called Xfinity over a month ago, this happened on Oct 25th.. and was on the phone for over 15 minutes with a very friendly woman with a foreign accent on the 26th of October who said she could update my account for me with the new bank information. I do not go on online accounts like this, and never will again.. this is the FIRST time I have ever logged onto this Xfinity online account. I hope I never need to again. My bills are paid and paid on time and  I put up with all the silly outages when it even lightly rains, and service interruptions when you have no service for 2 hours because of updates and this is what they do to me. Apparently the girl on the phone DID NOT know what she was doing or did not do it correctly, and after 15 minutes on the phone when we hung up.. it apparently did not work. So on November 11th the Auto pay apparently got denied because Xfinity was trying to deduct it from the old closed down account, not THE NEW ONE like they were supposed to. Now I've gotten late fees and a mailed bill they want me to send it. I was confused, I'm on Autopay, why would they mail me a big bill and charging me fees and the last month bill not go thru because they updated the new bank information??? So today I got out the log in info they gave me when they set up the online account and I see they STILL have old damn bank account info listed. SHE DID NOT CHANGE IT. That is not my fault. So I called in, been talking with a friendly agent, but the online account will not let me add the correct new bank information and says I am blocked from adding a bank account and only can use a credit or debit card. I WILL NOT USE A CREDIT CARD UNDER ANY CIRCUMSTANCES and pay interest on my internet and phone bill. Its not my fault she did not do it correctly but now they don't trust me to use my new account. I was on the phone just now for over TWO HOURS with two different customer service agents, one in the Security department who escalated it to higher supervisors and they still said no to allow me to put the new account on. They said I am free to use credit or debit card or find another phone and internet provider!! Wow. They don't care if I leave?? This was their screw up not mine. I have an 820 credit score and am a responsible adult, I do not pay bills late ever, and certainly with an Auto pay situation, it is not my fault. Guess I'm calling around tomorrow for new phone and internet, maybe I'll go back to Century Link, had them years ago. Can't believe security supervisors at Comcast/Xfinity are treating me like this was my fault when it was theirs. The girl on Oct 26th told me she updated the new bank info and removed the old account. This was weeks before the Autopay date of Nov 11th. I did was I was supposed to do. Now they won't let me add the new bank account at all. Who goes to work at customer care at Xfinity with a brief case and a suit and tie.. and this DOESN'T bother you? Shame on you Xfinity.  I did my part. She didn't update the account correctly, not my fault. Can't believe they would treat a loyal customer this way.