Not sure I follow. First, blackberry data services work over wifi (provided you have a blackberry data plan, of course). At least as far as I know this is universal and not dependent on service provider.
If it isn't working, or was and then stopped, the usual troubleshooting steps would be the first thing to try: Pull battery for 30-60 seconds with power on, then try again. And resend service books if that didn't do it. After that, I'd call customer service.