I purchased an IPhone X on ******* *I asked the seller if the phone was unlocked to whi...

I purchased an IPhone X on ******* *I asked the seller if the phone was unlocked to which he replied “yes” *A day later I asked when he will ship and he said I will ship it in three days because I’m waiting for T-Mobile to factory unlock it. *Then only one day later he shipped it. *I received the phone and it was still locked so he told me to wait a few more days. I did. Here it is almost a month later and my phone is still locked. I have contacted T-Mobile and they said the only way to unlock this phone is if he calls them and says he wants it done. This item was not falsely described to me. Also I cannot contact him for him to have the phone unlocked and he is saying I’m lying and that’s it is unlocked. *What can we do to resolve this because I spent $*** on a phone that i cannot access. I have all messages with proof if needed