I would never give TMobile my bank account or debit card information. They've had data breaches that have disclosed customer account data, including payment data, out into the wild. From: https://tmo.report/2023/06/everything-you-need-to-know-about-the-upcoming-t-mobile-autopay-changes/ :
Clearly this isn’t a very popular idea among T-Mobile customers. On Reddit, users have complained about the upcoming changes, with many saying “I will never give this company access to my bank information”. Others say they will leave T-Mobile all together once the changes are made.
Customers are right to be worried. Just this week T-Mobile had their 2nd data breach of 2023. It affected just over 800 customers, while their previous data breach in January affected around 37 million. Overall, there’s been at least 8 data breaches since 2018."
I am sure that the only reason T-Mobile is doing this is because they got stuck with paying the whole bill for customers who paid with a credit card, while debit card holders can be held responsible for up to $50 of of a fraudulent transaction. This is a really bad deal for T-Mobile customers, who should RUN, not walk out on this company.