Returned equipment still being billed

I called and cancelled my 5G internet service in April 14 th 2023. I also was billed 50.00 I was sent a return UPS form after my cancellation. It was sent on 04/24/23 and arrived in FT. Worth Texas which is overnight on this type of service. It was received by TMO left at dock. I have made over 60 phone calls about this matter to a 600 dollar a month slave labor CSR in the Philippines. I think all companies that incorporate Pilipino labor should disclose to the customers what they pay for these people. I consider this slave labor just as the Chinese slave labor. Thank God the Chinese people do not speak English, or we would have Chinese CSR working for 10 cents an hour by this low life company. I got my May bill for 50.00 so I called the CSR Group in the Philippines, and they sent me another UPS label with a new tracking number. So now I have an outstanding UPS Label that says I never returned my equipment. I my 68 years I have never delt with a more inept corporate organization than T Mobile.