Hard/old food

I ordered a Hamhattan sandwich off their menu. The Parma Ham they put in the ham was hard around the edges and too difficult too chew. Their explanation for it was that it was cut off the edge of the ham. When I complained they returned with only half of the sandwich, even though I had only taken one bite from the one half. They said that it's the best they can do and I should deal with it as they were doing me a favour. This happened now at 15:30 today. No refund or full sandwich given.