Error in Billing

I was on a repayment plan for my mobile service.  The regular scheduled payment was deducted from my bank on Jan. 16th.  For some reason, my normal monthly payment was not taken as well.  I received an email that informed me I was late and my repayment plan could be in jeopardy of being terminated.  I attempted to call in on Jan 21st, but waited about 45 minutes and decided to use the chat option.  I asked why it says I missed a payment on my repayment plan.  An amount of $83 was taken out on the normal scheduled time.  I had just recently made a payment on my normal account for $252.00.  I am attaching the screen shots of the chat to further explain the situation.  The chat agent informed me that there was a glitch in the system and that I was all caught up and that the system will update in a few days.  Fast forward to Jan 26th.  My service was disconnected for a past due balance.  I called in and spent almost 50 minutes with billing before they could find out what the issue was.  I was told that the repayment plan and the regular monthly payment had to be made at the same time.  I don't know why  my monthly payment was taken off of autopay.  Anyway....  I explained that had that been explained to me on the chat, I would have remedied the situation and my service would not have been interrupted.  She didn't seem to care...  I moved all 5 of my lines, plus purchased 2 new iphones, from ATT less than 6 month ago.  I had been with ATT for over 20 years.  I made the wrong decision.  I should have never left ATT.  Xfinity does not know how to keep customers. I was told that i could not speak with anyone about this complaint.  No one seems to be able to keep me here.....