Blocked iPhone 12 Pro max

At Christmas , I bought myself a 12 pro max from a pawnshop “ great deals around the time” and it was AS IS. Well, come to find out, it’s blocked by T-Mobil , and called them… T-Mobil told me to get back to the pawnshop so they could discuss the matter,I did so , manger of PS and customer support talked to each other. PS manager stated “ if it was stolen, no way would the person who pawned it know the password or code to delete the information or iCloud and erase the phone” what it came down to, t-Mobil wouldn’t give me information about the owner, nor the PS manager, so I went to a T-Mobil store and although they couldn’t help me activate the phone, they did tell me there are people who could do it where it’s I could use it, just not on T-Mobile or Sprint… well, I still can’t find anyone, anyone knows anything that may help me? It’s my gift to myself!!!