How about you just try and reconcile both contradictory points as best you can. I bet it will be some ideological Libertarian fantasy, but please do have a go.
I imagine it'd be the same as every other vital service that's paid for voluntarily. Food, water, medicine, transport... none of which I think are figments of an elaborate Libertarian fantasy ;)
Perhaps you could explain why you believe the provision of Government services is an exception that requires compulsion?
Perhaps you could explain why you believe the provision of Government services is an exception that requires compulsion?