Mobile billing issues and no supervisor

I received my upcoming bill today as it was $35 more than the prior month. I have only been a mobile customer for approximately five months and my bill has been the same every month. However, this month it went up $35. I called customer service ( shocker not domestic call ) and spoke to a representative who told me that the prior month credit was applied incorrectly. I told him that it was not because the bill has been the same since I transferred over to the mobile. Then he tried to tell me that I was no longer getting the credit. I tried to explain to him numerous times that when I signed up for mobile, I have a device and credit and buy one get one free line for a year. So my bill should stay the same so approximately October the incompetent representative was not understanding what I was saying , I asked to speak to a supervisor. I waited on hold for 52 minutes and then transferred without being told to a line that just kept ringing. It rang 100 times then disconnected.

So again I have spent two hours on the phone with Xfinity , trying to resolve an issue and there is no resolution. I wish I never transferred my mobile service over to Comcast.