IMEI Blacklisted on my Iphone

I've just had a very similar situation unfolding the T-Mobile team were very good so were the support team from Apple. In my case the IMEI two number was blacklisted and blocked but not by T-Mobile and Apple had no part in this. I took the above advice and went online and found out that Xfinity mobile For some unknown reason had blacklisted my phone I've now got off the phone from them with a part apology that was all garbled and incomprehensible but no proper apology given they did promise to sort out the problem, and make sure that the blacklisting was going to be removed. Let's see in the next few hours and if by the morning, my phone is not sorted out the gloves off and I will bring the CEO of Xfinity into this mess. How the hell can an unrelated company  block and blacklist you at will. This is crazy.  I've been a client of T-Mobile for 17 years And unfortunately they were not there to help me sort out this mess. I feel they could've gone the extra mile and found out a bit more on who was the culprit that created so much anger within. Xfinity put a 17 year relationship under duress. They should be ashamed of themselves.