Sounds like HSBC to me! They returned a business cheque of mine the other day because they thought it was fraud, I'd bought £1300 of paving slabs (i'm registered as property maintenance!)
Best bit is... When i went to explain myself and pay it off with the card, the little machine told them to call someone, where they promptly told her to keep the card and call the police, as I had obviously stolen the card!!
Took 3 15 minute phone calls to sort it all out and just got a 'sorry for the inconvenience' from the fraud team bird who couldn't even speak my language, let alone pronounce my name, who then advised me to avoid fraud by not discussing my account with people who sound foriegn!!!!!
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