Xfinity claims unlock is done but still cannot switch SIM cards

Xfinity mobile claims that both of my iPhone 11 are unlocked. Yet after putting in a Tmobike SIM card, I get a SIM card not supported error. Xfinity claims that its Apple’s issue. Apple activation server says phone is locked to XM. Anyone having same issue where XM is being mischevious? I have been with their CS for past week almost every day and although they are nice, either everyone is incompetent or their systems don’t work. Anyone having similar issues?