It's a Sprint issue. Everyone has had problems with Sprint (going back to at least 2004 that I'm personally aware of).
Find a Sprint store, bring the phone in and ask them to fix the provisioning on your account. If they can't, won't, or that dfoesn't fix it, and they won't call Sprint (most Sprint stores are individually owned), find a company store and try there. It may take Networking watching the tower as you turn your phone on, but there is a way of finding the problem.