Un-Authorized Charges

I had a payment arrangement on my account for 8/3. I went into the arrangement on 7/31 and paid a partial payment from the modify arrangement option. Now on 8/3 instead of charging what was left on the arrangement, XFINITY charged the whole arrangement sending my account into overdraft. I spent hours on the phone this morning trying to rectify the situation and I was hung up on by a supervisor who was not listening and kept telling me I should have canceled the arrangement before making a new one. How and why would I have know to cancel an arrangement if I was already in the arrangement using the modify arrangement option when I made my payment. Instead of listening and trying to find a resolution she just overtalked me and finally put me on hold because I asked to speak to her supervisor. I waited on HOLD on about 10 minutes until she hung up. This is unacceptable. My account is in overdraft now. I have filed a complaint with the Better Business Bureau . Because the amount that was taken was unauthorized all that had to be done was refund that amount and then do another transaction for the correct amount. But because the customer service piece for xFinity/Comcast is more than like a third party no one cares and just follows the script that are given. When requesting how to reach corporate or an executive customer servie agent or an actual xFinity employee they tell you htis is the highest lever of customer support for xFinity. Something has to be done with the Customer Service provided by Xfinity or there outsourcing company.