Oh dear. They do appear to be a properly regulated company according to their website - but you don't know that the chap was from there... at all. He may be and it may be OK, but you should never give any details to someone who rings you out of the blue, it could be anyone. Go tell your bank on Monday, or if you have on-line banking, see if there is any way that you can block the transaction before then. I would be suspicious however of any loan company that asks you to pay anything upfront - what for? - I have had several loans over the years and never had to pay anything to anyone until the first due date after the money's in my account.