I work in a COR store, and we haven't been able to resolve this issue, and I'm on the phone with inexperienced tech help. This customer has a cingular Go phone, the monetary balance is not an issue, we've tried multiple phones, brands and different SIMs, but it wont make or receive phone calls. It tries to connect, it fails every time. Anyone have any suggestions? The OTA has already been re-sent. Thanks in advance for any suggestions.