My Dad did this with a holiday company who had knackered our holiday. They expected us to the foot the bill for a change of hotel because they decided to change their policy about allowing children into a hotel, when our travel agent asked for confirmation and they said there were no problems. Then they rang us two months before we were to leave to say the holiday had been cancelled.
Getting back to the original point, my Dad set up a telephone with a mic and mini disc recorder and started recording the conversation. The company had warned that they may record calls for training purposes. So when he got through he made it clear that this conversation was being recorded. The woman on the other end said, 'You can't do that!' My Dad said that they were doing the same thing for 'training purposes'. She refused to talk to him any further so my Dad said that he promised to stop recording aslong as no recordering was going on at their end. She agreed and my Dad pointed out that if this conversation was to turn up in the future he would not be pleased. Baring in mind we have this small conversation of agreement on the mini disc
Any how you will be pleased to know that the holiday comapny ended up paying for us to go to what turned out to be a much better hotel.