Stale Deli Guava Roll

I bought a Deli Guava Roll at the Clicks pharmacy in Middestaad Mall, Bellville. upon eating the guava roll I found that it was stale. I did not think to keep the product or packaging because I did not know it would be requested as I had already eaten some of it. I sent an email to customer service, recieved a response that there is nothing they can do as I no longer have the product or packaging. It is my understanding as a customer who has the in-store rewards card that it can be used as proof of purchase should it be required, because of this I feel other resolution tacticts could have been used before being told they can't do anything.