Very poor service

I made a booking through hotels.com. Accommodation showed that they had rooms available. Payment was accepted and I received an email stating that the booking was guaranteed and paid for. Out of courtesy, as the booking was already guaranteed, I forwarded the email to confirm if it was all in good order. I received an email stating that they had no rooms left and I should find somewhere else to stay. This is after they took my money. This constitutes unjustified enrichment and breach of contract, coupled with the unprofessional service.