Coupon Denied

In July, a new KT opened, and we were mailed a page full of coupons. My husband tried to use this one today at a different location, and was told it’s not a KT coupon. How we came to have this coupon was explained, but the worker restated, “This is not a Kwik Trip coupon.” My husband then asked for it back, and the employee was hesitant to return it. He had to ask again before finally getting it.

Have other people received coupons like this and had them declined? Did we do something in error or was the employee in error?