Samsung Pay at&t + N920i

So I just bought a 920i version from eBay (monoprice store). Brand new unlocked. I am on at&t. Downloaded the Samsung pay apk and after signing into my Samsung account via Samsung Pay. After signing in I am getting this message "You must use your own Samsung Account to use Samsung Pay". Well, it is my own account.
So question: Has anyone got Samsung Pay working on N920I with a US carrier (more specifically at&t). Do you have a solution to this problem? Thanks in advance!