ShopRite email compliant

I sent my local ShopRite a complaint email regarding a coupon that I activated online at ShopRite.com that I did not get to redeem. I went to the the customer service desk and got the 40 cents that I was owe. My husband laughed at me when I told him about the email. He said I was right to send the email but laughed at the small amount. I am not ashamed of being frugal! I'll write if/when I get a reply.