Unlocked Blackberry, service does not work?

I recently subscribed to a new blackberry service through AT&T on my unlocked Curve 8520, which I bought in Dubai. I've used it in other countries through wi-fi, as well as here in South Carolina on wi-fi. I subscribed to one of the new plans, which offers 100 mb of data for 15/month. Since subscribing and rebooting, the browser services have worked, but BBM and email has yet to begin working. I've tried a soft reboot and a hard reboot since. Is there anything else I can try? Or will I need a new blackberry? I'll be in the states for a few years, so.. Any help is much appreciated.