Round Table Pizza review: branch customer service

I called to make a delivery and I'm using a coupon that you had provided me on my last delivery. I ordered pizzas from you probably 8 times a month which equates to about $350 a month that I pay to your establishment every month. The coupon that I had provided said I could have a specialty pizza for 2299 and I believe it was a large. the person I talked to on the phone said no sir I'm sorry that coupon has expired and put his manager on the phone who also stated the coupon had expired. I imparted to him that I'm a frequent customer who orders a lot of pizzas in during baseball season sometimes we order $300 worth of pizza every week. He stated that I could get a specialty pizza for 25.99 which is a $3 difference from what the coupon I said was given to me. He would not budge and proceeded to argue with me for 30 minutes and I'm sure if he is a manager he's probably paid an okay wage and he wasted a half an hour over $3. I'm a general manager of a company and I just wanted to point this out as a possible training opportunity for your staff. I do not want anything in return I'm not asking for a discount I'm not asking for a free pizza I am telling you that you would take an extraordinary response from your company 2 ever have an opportunity for my business again and I will leave it at that