Billed wrongly for past 6 months

Hi Team,

I moved from tmobile to xfinity 6 months back. I purchased iphone 14 pro with xfinity along with porting my number on a credit of 500 during purchase which will be applied every month that was deal.

When  i got the phone , tech team tried to active "esim1" from iphone but it was not working so they activated "esim2". 

But looks like xfinity credit was applied to esim1 and they charged me for 2 numbers and after a month they closed esim1 and the credit applied to that. Now i am being charged full price for the phone for last 6 months. I have called n' times they applied credit for 2 months and they stopped again.

Is this my problem if xfinity members does a mistake and we are being impacted. I called xfinity agent they will make us to wait for hours and at the end, we created a ticket it will resolved nothing [Edited: "Language"] happens after that. When we chat with agent they say issue will be addressed by advance team and nothing happens.

How  to escalate this issue, there is no way. I am litterly stuggling with this issue, ready to hand over the phone and internet connection everyhting if they pay me extra charges. Its really frustration when expected response or issues   not being answered. I really don't know how to resolve this issue with xfinity. I never had any issues with their internet but mobile , oh my god very very poor response and carelessness from the advanced team.