[VoiceOps] Main number fail-safe solution for small ITSP

I'm curious how other small VoIP providers handle having a fail-over for their main (support) phone number in case their entire infrastructure is unable to take calls. I know we all build in redundancy, but for the big what-if scenario where nothing is available and the calls fail, you still need to take your customer support calls. We have one carrier who does PSTN failover, but they're far from our primary or an ideal carrier for us. None of our major origination providers do this. -- Carlos Alvarez TelEvolve 602-889-3003