Timezone has nothing to do with the initial verification call, if it doesn't come through within 15-30 minutes there is an issue with our system, your system, your provider, their upstream or our upstream providers are unable to send a call to the number you specified.

The system will allow you to re-queue the call 3 times and then you'll need to contact support to unlock the number, the reason numbers get locked is to prevent people abusing the system and sending calls to someone else to annoy them.