I'm trying to help my Dad (age 95) get his new phone working. He recently swapped his vintage Kyocera K7 Rave for a Coolpad Snap. Activation seemed to go successfully (thanks to VM's telephone support), and everything about the account and phone settings seem correct, but he cannot place calls. He gets either the "Sprint external operator" message or the "unable to complete call at this time ... message 12" message. Any suggestions? Help from the VM experts would be appreciated.