why can't Comcast implement contract renewal? being charged 3x

I renewed 2 days prior to contract expiration. Initial service agent didn't process the renewal. I was charged 3x since I was on autopay. Contacted her and her manager. No results. I took it off autopay and contacted Loyalty Dept. Told them I would cancel if the contract renewal isnt backdated. Instead of backdating, the month-to-month rate stayed on and the next bill generated with the high m-t-m amount. I was told by Loyalty that It will correct before the due date. Today is the due date and it is still not correct. I am debating cancelling. I have already activated alternate service that is low enough to act as a backup system but robust enough to be the primary system. I am up to 5 calls and 5 emails so far on this issue. How long does Comcast expect someone to work on a process that should be automatic and smooth? I feel like this is a way for them to get extra revenue by taking advantage of distracted business owners. Right now, if I cancel, I can only do it by cancelling the contract rate. Once I do, I would owe the m-t-m rate for at least a two month period. This is what happens when there is no competition in the market place.