Bear in mind that customer service in the UK is often terrible especially compared to the US (I've been fortunate enough to live in both places) and I've found that some inexperienced or bad customer service people threaten legal action without even being serious about it as a sort of a threat. I was threatened legal action by a car rental company for something related to a flat tire that was nothing to do with me and I had even dealt with the situation at the physical rental place just fine. Nevertheless some representative contacted me several weeks later to threaten me, I told them to stop it and then they never contact me again, several years later I've never heard from them. It's bad customer service. If you call their bluff and say ok, sue me, they'll be surprised. This case (as was mine) sounds so clear cut that why should you feel intimidated. They would lose.
