I bought a slab of Cadburys milk chocolate and tried to melt it over low heat on the stove, yesterday the 5th September, I then attempted melting it in the microwave, it made no difference. The chocolate would NOT melt and rather the whole consistency changed, it looks similar to a ball of gravel. I was very surprised as I have melted chocolate in this way for years. I attach the photo so that you can see the problem. Please advise, have the ingredients changed or what could be the problem? Thanks Nicolette