Unauthorized transactions by Xfinity

These people are thieves.  I called them because I set up an automatic payment for a future date for a certain amount.  They changed the amount without my permission and more than doubled the amount.  I called them multiple times and they could not provide a reason why they did this.  I asked to speak to s supervisor.  They had me on the phone for about an hour, did not get me on the phone with a supervisor, they did not resolve my issue and they hung up.  I spoke with someone claiming to be "Camille" by the way