Chicken Express

I provided a coupon to the cashier who took my order and he did not use the coupon or give it back and when i asked why. I got a "I dont know." Then i had to pull up to the window and and even the manager said there is nothing they can do and basically were very rude. I go here all the time and is known as the lemon guy and if this does not get resolved i will never be going back.