T-Mobile Unauthorized Charges & Unreturned Phone

I recently switched from T-Mobile to Verizon and returned my old phone to T-Mobile. However, without my authorization, T-Mobile charged my credit card for the phone. Despite multiple attempts to resolve this with customer service, they have refused to refund the charge. This issue has been ongoing since November 7, 2023, when I returned the device. On December 30, T-Mobile deducted an additional $189 from my account for the phone and service charges. Despite my repeated requests, T-Mobile has not returned the funds or customer service provided any explanation for the unauthorized charges. I am writing to demand the immediate return of the funds, as this money rightfully belongs to me. Thank you for your support.