Xfinity won't unlock my phone Even after paying off phone and having met all guidelines.

I want to switch to T-Mobile. I paid off my phone and been with Xfinity for a year. I have contacted Xfinity support almost 15 times already and about 10 chats with them and they keep saying that the device is already unlocked but here on my end, the device keeps saying that is still lock. I even call Samsung and it's showing lock to Comcast. Idk what else to do. I bought this phone from Xfinity store about a year and is just not working.