Data connection refused usually means that you either blacklisted (haven't paid your bills), have not been provisioned on Cingular/RIM systems yet (takes time), or there is a problem on Cingular/RIM networks.
You are new user, you shouldn't have unpaid bills, your best bet is to wait until Monday afternoon. By that time you must be properly provisioned and if there were any troubles on the network they will be sorted out.
It is also not unheard of for a wireless provider to make a mistake and not actually enable your blackberry on their or RIM's network.
So, just wait. Give call Cingular Monday afternoon. By that time, if you still have Data Connection Refused, that most definitely be some kind of Cingular error they will be able to figure out and fix.
I hope you can find something else to do on the weekend.