Kroger credit?

I let a family member use my Kroger card (I'm a employee) and it has my employee discount on it but they where able to use credit to pay for the purchase which baffles both of us. One I have never signed up for a Kroger credit card. Two it was just the simple Kroger card that anyone can get. Would there be some employee bonus credit that was tied to my discount on that card or is this something fishy going on?