First, you should know this is a customer to customer forum and, while DreamHost staff occasionally drop by, they rarely post here. If you have an issue you wish to discuss with DreamHost, you should use the appropriate channels for that: filing a support request in the control panel, replying to a tech support email, or using the contact form at http://dreamhost.com/contact.cgi.
That sounds about right to me, from what you have described. By using the promo code from your first account when you opened your second account you fraudulently obtained a discount that you were not entitled to receive (you were not a new or "first-time" customer).
Well, the TOS prevents you from opening multiple "plans", and warns that all plans will be terminated if you do (See paragraph 8 under Material Services)"
"The Customer agrees to hold only one (1) active web hosting service plan at any given time with DreamHost Web Hosting. Signing up for multiple plans is grounds for termination of all plans, including the first one, without warning."
That said, there is a way to "add accounts" from within the control panel, and they allow you to do that for accounting reasons, but not to do it as a "new" signup with a promo code discount.
You should seek any further explanation directly from DreamHost; I don't know how anyone here can help you.
As for getting your account(s) re-instated, I cannot speak for DreamHost, but I would be very surprised if the continue to business with you after having terminated your account(s) as you described.
I can understand that you are unhappy about not being able to continue to host your sites on DreamHost, but if it were me, I'd just move on and find some new hosting as soon as possible.