GOODS EXPIRED OR LOW QUALITY MEAT BEING USED?

I purchased a beef sausage roll for my 16 year old son today from London Pie at the Checkers Hyper Centre off 14th Avenue. From the first bite my son noticed an awful taste from the sausage roll! we were already on our way home when my son just couldnt eat it anymore as the stench and taste was so disgusting that he wants to vomit!! I am unsure whether this was a product that had passed its expiry date or just bad quality meat being used??!!! but at the price of almost R20, this is absolutely ridiculous!!!