Connection failed mid-way through, so I booked again. Now I've been charged twice

I recently used lastminute.com to book a double room at The Clifton Hotel, Scarborough, part of the English Rose Hotels group. The internet connection failed before the transaction was completed, so I used the same website to rebook. When I arrived at the hotel check-in the next day, staff told me I had booked two double rooms. I said that, so far as I knew, I'd only booked one, and only needed one. No more was said. (25 September 2010)