autopay unenrolled that has nothing to do with me

I recently received a few emails stating my account was changed and that I wasn't enrolled in autopay anymore. I called verzion to ask why this happened and was told it was because my bank showed insufficient funds and automatically unenrolled me from autopay as a result of this. I logged into my bank account to verify if this was the case at the time of taking money out... and there was around $900 in the account. I argued this point several times with verizon representatives and managers just to be told that the only way I could have autopay enrollment again was to sign up for it. WHY SHOULD I sign up for it when I did nothing wrong? I wasn't in error. I don't care what took place between your system and my banks. THE MONEY WAS IN THERE. How do I know that's what happened? What if there was some glitch that caused this? If the money was in there, which it was, WHY AM RESPONSIBLE for reenrolling? I did this once in the beginning... now I have to pay the price and do it again? YOU DO IT. YOU took it away from me, YOU fix the problem.