On Friday, did you "check eligibility" for an upgrade as an existing IUP member, enter your current phone's serial and IMEI number, and receive upgrade eligibility information? Or did you sign up for the program and go through the whole credit check process, etc online? If you did the former, you would have picked out a phone and made a reservation to pick it up in a store on Friday to complete the trade in. If you did the latter, you basically started the IUP again from scratch and created a second separate loan, instead of a trade in on the original loan.
Existing members = reservation to pick up phone in a store on Friday
New members = actual preorder being shipped to your home