I bought someone an expensive water bottle as a Christmas gift. Today they handed it back to me and said I should return it because its only single walled so condensation develops on it when they put icy water in and I should try and get a refund. Partly my bad, it didn't claim to be double walled and I didn't think of it when buying, for me it doesn't matter as I just fill from the tap and keep it in my bag on my desk. They maintained this water bottle is not fit for purpose and should be returned under distance selling laws. I don't think I have grounds to return it on this basis. I'm not sure what to do, they insisted they didn't want me out of pocket for something they can't use, but what should I do? I'll happily take it and use it myself if they don't want it. I can't return this item can I? I know this is trivial!!