Xfinity refusing to unlock phone

Xfinity Mobile is refusing to unlock my fully paid off iPhone, which has been on their service since November 2023 FULLY PAID OFF might I add. I’ve spoken to multiple employees, and they keep telling me that since I didn’t purchase the phone directly from Xfinity, they can’t unlock it. But Xfinity has been the only carrier this iPhone has ever had. This goes against FCC rules and isn’t fair to customers.