How come my newly added contact's number does not work?

I just signed up for a new contact and the local number that Rebtel supplied is not working. I get a message that this call cannot be completed as dialed and to check the number again. I checked both the original number and the one rebtel gave me and they are correct and I am dialing it correctly. I did get an email confirmation from Rebtel, so I know the number should be activated. What needs to happen to make this work?