Device payment plan - zero credits

I have been trying for some time to find out why I’m not able to use the payment plan for a new phone. I have unfrozen my credit reports and nothing changed. Online and in person agents have no answers. I’ve spent hours going around in circles. I have good credit and have never been declined for a phone plan. I’d like to request a manual review to see why is going on. I switched to xfinity internet solely to take advantage of the iPhone deal that I now missed out on. This is frustrating.