I had the same experience with them and when I told them that I'm not going to give them any information over the phone because I have no way to verify anything I was told is true so give me a phone number I can contact them to verify the transaction then I was told that I'm overly cautious and stupid phrased in a nice and British way. And the transaction they flagged was a £30 payment in a city restaurant. I'm no longer with them.