Who called me from 03302009900?

Scam call from a caller who said he was from Barclaycard Fraud team - he wasn't as it turned out. I've never fallen for a scam of any kind before, but stupidly I fell for this, it was quite sophisticated. The guy wasn't offshore - I believe he was UK based, and very well trained. He said that they (Barclaycard Fraud) has spotted suspicious activity on my card, and checked some recent transactions with me. I didn't recognise them, so he said he would "cancel my card", and block the pending transactions that they had put on hold. For those transactions, he asked me read an OTP (one time pass code) text message from Barclays back to him. As it came from the same number as previous Barclay messages, I believed him and read the code back.... stupid of me and a mistake. Of course what he was actually doing was putting a purchase transaction through and getting me to give him the OTP. He also went through the charade of talking me through going into a branch with two forms of ID to sort out the issue. After the call we checked the Barclaycard fraud team number, and it wasn't the same. The scammers are using a very similar number to the real Barclaycard number - i.e. they are using 0330 200 9900. The real number ends 9090. We reported it soon after the scam call and Barclaycard are sorting it out.