When I worked at a grocery store, I had stuff like that happen all the time. People would eat half a bag of whatever-the-fuck and then demand a refund because they "didn't like it." Well, damn, if you didn't like it, why did you keep eating it? Plus, we're not in the business of giving refunds to people because they bought shit they don't like.
One lady bought some bean salad stuff and came back the next day because she said there were mouse bones in it. She had even picked out some of these supposed "mouse bones" and brought them in to show us... they were pieces of the stem from the top of beans. She refused to believe me, even after I showed her identical "bones" on the beans in our produce department. Apparently she didn't have the rest of the bean salad, either, and she couldn't give me a receipt for it.
Weird things that people did return stuff for that was actually true:
- a chunk of wood in a jar of sauerkraut
- a grasshopper in a jar of pickles
- a potato chip that was completely black