Denied phone claim mistakenly says phone not covered

I brought a  phone from a different carrier- I didn't know there were different insurances and the employee put me on a T-Mobile insurance plan instead of the BYOD plan. When my phone broke i  filed a claim and it was denied because I didn't have the byod plan. I called customer service and they switched the plan for me then had me file another claim. The claim was denied again. This time they expedited it to assurant speaking to the supervisors but they still denied it because I put the wrong model phone even though the imei number is right they won't even let me file another claim correcting the phone model. T-Mobile said there's nothing they can do even though I've been paying the insurance and the phone is paid off. Real pyramid scheme