There are lots of reasons it might take much longer than a few hours. DreamHost has a pretty extensive fraud detection system that is triggered by many things, and they do not share publically what triggers it for security reasons.
Past information shared here by others indicates that addresses, phone numbers, country of origin, method of payment, and IP address as related to those things are some of the things can can cause your request for an account to be flagged for human review.
This does not necessarily mean that you did anything wrong, or that you account request is considered fraudulent; it only means a person will have to review it before account creation can proceed.
This is Monday morning in the U.S., where DreamHost is based, and many of the administrative staff do not work on weekends, so it is likely that your account request is in the queue, along with your support request, and will be addressed in turn.
I'm sure that they will respond to your ticket, but am not surprised that you did not get a response about the status of your new account over the weekend - it was likely forwarded to those that will have to deal with it during the work week.
I hope they get you set up soon!