T-mobile stores are explicitly forbidden to help you cancel service. At the branch I visited, they insisted they were physically unable to cancel anything. It is possible they were lying, but equally possible that corporate did make it impossible for them.
We tried to cancel my mother-in-law's account. Even after they got a copy of the death certificate, they still refused to cancel.
About all you can do, usually, is cancel the credit card they are deducting from, or maybe to get your bank to reverse their charges and refuse any new ones. Do not ever give T-mobile rights to charge for your account, monthly.
So strange. Just before the pandemic, I went into a T-Mobile store and cancelled my hotspot service. No problems. Perhaps it's a regional thing? Or a performance issue for a particular store?
We tried to cancel my mother-in-law's account. Even after they got a copy of the death certificate, they still refused to cancel.
About all you can do, usually, is cancel the credit card they are deducting from, or maybe to get your bank to reverse their charges and refuse any new ones. Do not ever give T-mobile rights to charge for your account, monthly.