Do nothing. You're fine. They can't bait+switch. Arbitrage happens.
Originally Posted by
deant
The first step should be to send an email to the hotel requesting clarification (William or one of the others can give you the address if you don't have it).
Why? Emailing just brings attention to the matter. If you book at a cat3 rate, you pay the cat3 rate. Consumers have rights. In most countries, I think..