Assurant bad customer service no help

I've been customers for tmobile for 7 years and I am planning to switch providers because of how I uncomfortable I am with them. I claim a phone lost on August Iphone 13 pro max, assurant send me a replacement Iphone 13 pro max but actually I did received an Iphone 15 pro max, I thought they did not have my phone or upgrades my phone because other one was old. I was able to activate in my account the 15, so No issue up to now that I want to switch carrier but phone is carrier lock and tmobile said there is a balance on the phone and bought on different account and assurant said that they never send me that phone that they send me an Iphone 13 pro max. I just need my phone carrer unlock but assurant customer service is being nasty when call and tmobile can't do nothing because they go of what assurant have in their systems. Right now I have a phone that I can only use on tmobile and pissed me off that nobody want to help and I prefer to move my 7 lines out of tmobile and no to suffer any more nightmares anymore. I submitted a complaint to bbb, and fcc to see if they can handle from there.