No Costco? Go to Menards. The store is just enforcing policy. This has happened to my folks before. They bought a microwave and didn't open it until like 4 months later, damn thing worked for 2 or 3 months and quit. Unfortunately it was out of store warranty so SOL. I would contact the manufacturer and take it as a learning experience. I usually pop things open as soon as I get them now.
Did Menards ever move south? The only time I seen them was when I was in Indiana.