Has anyone else been scammed by Booking.com (UK site)?

Booking.com UK site offered me a 3 star hotel room in Milan for £18 - with no cancellation fee.  I took the offer and got a reply telling me all was OK and the price was 12 euros.  Twenty minutes later, I got another email telling me it was a mistake and the room would be £323. I cancelled.  I'm willing to go along with this being a genuine mistake, but it could be a scam to get customers to commit.  If a number of people have had this problem with booking.com, I'm prepared to prosecute them.