I think the guy is getting scammed buying gift cards

I got this old guy that come in almost every day to buy hundreds of dollars in gift cards done so for the past 3 nights. Hes kinda an a hole. I told him we can only do a certain amount in cash for a load at night (so we dont have too much money in the drawers) i didnt tell him that part. He goes FORGET IT! then decided to just do the smaller denominations. He yells across the store if im not up there right away. I work alone at night. What should I do? Idk what he will do of i try to stop him. I am trying to limit his purchase incase im right and hes getting scammed