You cheat us with your coupons

Issued me a coupon for an item that I returned, not because I'd changed my mind but because the item delivered was not the item as pictured. I asked for it to be credited to my account but no, you issued me a coupon. Valid for 21 days! This is against the CPA. On requesting for the validity of my coupon to be extended you refused and the coupon expired. This is unacceptable!!!!