With 2 nights at $300, it's not a 'mistake' rate (aka, $3 rate), so they can go pound sand w/ their $600 IMO.

To the OP - my recommendation (and I speak only for myself) would be to email back Rev Mgmt & tell them to honor the originally booked rate or the New York Attorney General as well as the media will be contacted. Don't back down on this.**

BTW - don't know if the OP did this or not, but whenever I book a (fill in the hotel chain) reservation I immediately put the email confirmation into a folder on my computer, so that if the (fill in the hotel chain) tries stuff like this/changes the online reservation I have written proof of what was originally booked.

**Unless it is the $3 mistake rate from a few weeks ago/less of a leg to stand on. $3 obviously a mistake. But if it's $300, then full sail ahead as $300 can be reasonable/considered valid for NYC.

Cheers.