What should I do about a fly in my food ?

On a recent Thomson flight back from Mexico, whilst the first meals were being served I noticed that there was a fly flying around inside the plastic dish that had my chocolate desert in. I told the attendant and she changed it. After this we couldn't face eating any meals on the flight thinking about the standard of food hygiene on the flight and felt very anxious for the rest of the journey.When we got home I contacted Thomson to complain and was offered �10 each for the meals not eaten. I told them that I didn't think that this was acceptable. I have contacted them again this time I sent an email to Johan Lundgren who is MD of the Northern Region and got a reply from a secretary who said that the �10 was enough. And that they don't compensate for feeling uneasy and any disappointment. Should I take the money ? If not what next ? Also when I first contacted them I was told that it could of happened on any flight by any airline.