Fraudulent debit card transaction

dollywops

Last month, I won 2 items from an auction house. I bid via 'thesaleroom.com'. My debit card was charged as this is also registered on 'thesaleroom.com'. I believed one of the items was a fake, and I had this confirmed by a jeweller in Bond Street. I returned this by special delivery. The owner of the auction house was only prepared to refund the cost of the item, plus the buying fees. He refused to refund the special delivery charge and also did not refund the internet charges. In order for the refund to be processed, I had to give my card details over the phone, as I was advised they did not have access to my card details any longer. I did not pursue the lack of refund of the other charges, as it was not worth me getting aggravated. I did however make sure that the amount refunded was correct.

Fast forward to ten minutes ago, when I decided to have a look at my current account online. Said auction house have debited my account with an amount of £568!

Needless to say, I am very angry. Obviously, I will get my money refunded, but I want to take this further. They have obviously retained my card details, which I believe to be contrary to their conditions of being able to take telephone payments.

Perhaps someone knowledgeable can advise.