It's not obvious from the MyRepublic website how the voice service is implemented, and I don't see a support section or similar.
I'm guessing it's not VoIP via router, since the offered ASUS router doesn't have VoIP support.
So is it copper? Or is it being offered via the ONT?
If I had to guess it would be ONT since the FAQ mentions needing a technician to wire up the jackpoints.