Trying to upgrade my phone with no luck

I’ve been working with the local XFinity store to upgrade my phone to an iPhone 18 Pro Max for 2 weeks. Every time they submit a credit escalation, it shows up $0. I have an 816 credit rating, all 3 credit bureaus are unfrozen, and I’m a Diamond customer , paying on time every month since 2012. Please help me get this through!