About six weeks ago I had a small deduction from my credit card a/c by a short name I didn't recognise, - so I contacted security. I had only seen this name on-line to my a/c, and the person aswering said the likely explanation was that a small check-payment had been taken to verify my a/c details by a mail-order firm before sending the goods. She said normally I would not see it, and it would be cancelled by a deduction from the main payment, I would not see the split sum when the credit card a/c came by post.
Indeed this is what happened, I had only been aware of this name because of my direct access to my a/c, ... I had been too vigilant.
So if your debit is quite small, things may be all OK when you get the a/c by post.