Unfiltered Story #207198

(The system at our store changed a little while ago. One of the things that changed is the way we process buying gift cards. We have to swipe the card to activate it before the customer pays for the order. A variation of this encounter has happened countless times since the change.)
Me: Alright we just need to swipe the gift card.
Customer: *Starts to pay with their debit card*
Me: Sorry we need to swipe the gift card first.
Customer: *Continues to try and pay*
Me: *Swipes the gift card myself and lets it process*
Me: Alright so you’re paying with debit?
Customer: I already paid.
Me: Sorry, I had to swipe the gift card first. I just need you to pay for your order.
Customer: But I already paid.
Me: We got a new system and I had to swipe the gift card first.
Customer: Oh…So I have to pay again?
Me: Yes, you just need to pay for the order.
Customer: But I already paid.