I would go back to the local store and ask for the transaction ID number from the denial and contact ISP back with that number.
Also tons of places will deny if the foid number comes back as invalid. They do not bother asking any questions. Does your foid have a 8 digit or 10 digit number? There have been many people that missed being issued the newer foid card. If you have been issued a 10 digit card the 8 digit card is now invalid.