Repeatedly overcharged every month for internet

I signed up for Xfinity internet beginning in mid December of 2021. I was quoted a monthly price of roughly $35 dollars. The normal price would have been roughly $65, but I was told because I am an Xfinity mobile customer I would receive a $30 per month discount, bringing the total monthly charge for internet down to $35.

Every single month my internet bill has been $65 dollars (4 months in a row now). The first time I called in January, they were able to identify the problem after much back and forth with a very condescending customer service rep, who ended up crediting me $30 to my internet bill. Same thing the second time I called in February - they identified the problem more quickly and stated this was a known billing issue they were working on fixing. Again, they credited me $30 to my internet bill. In March it was a completely different story. I spoke to 2 customer service reps who barely spoke english, and tried to transfer me to the mobile department saying it was their issue (it’s not). They claimed they had no record of the past 2 calls I made which should have contained notes detailing the issue. I also asked to speak to a manager and was told “all of the managers are in a meeting and unavailable.” On this call they ended up crediting me $50 to my mobile account, which makes absolutely no sense. I asked for a call back from a manager. That never happened. I am beyond frustrated that this continues to happen every single month. Just got my bill for April and it’s once again $65. I am considering switching both my cell service and internet to a different provider because of the headaches and stress this is causing. Is anyone else experiencing this problem?