Tmobile Warranty not getting customer service help since January!

I had a zfold placed with tmobile warranty, and returned utilizing their packing package and label on time! Tmobile is still tying to bill me for the phone. 

Spoke with customer service and they adjusted the account and told me everything is taken care of and we should be charged.

In April we started getting a bill for the warranty replaced phone, don't they have a record keeping of notes or read their notes because I have to keep repeating myself especially after hours with outsources services. They mentioned our account will be investigated, they will disable our autopay and we just will need to pay for our monthly bill for now until they get back to us!

No one got back to us May we get another bill now it is a late billing notice for the phone, contacted tmobile again after hours, Rozz from customer service gave me the run around and try to have me acknowledged a payment plan! Excuse me this needs to be investigated and taken cared of under TMOBILE warranty! She said this case will be escalated and investigated. NO claim number provided to me no text or survery I am wondering if these reps are applying notes under our account or just throwing our concerns on the side? Now it is harder to follow up, dispute, or question anything regarding billing with an actual care team person. What would be the best way to contact an actual rep that could further assist my situation? 23 years with tmobile and first time encounterin a situation like this mind you I am still on hold for a rep and it is 32 minutes I am hanging up now!