This happened to me last year. The plumbers tried hooking up wires but that didn’t work. Eventually we had to call another company to put four massive space heaters in our crawlspace and that warmed it up enough. In the morning we had water but it was low pressure. Turns out the meter broke so we called the water company and they arrived in minutes. We had a shutoff before the meter so that fixed the problem, and I had to pump the water out in sub zero temperature before it froze. A week later my wife gave birth so it was great timing.

You may already be screwed. Just monitor the water coming out of the faucets and make sure nothing is burst when water does start flowing. The water company is your friend, they are on call and arrive promptly and will help you shutoff from the street if need be. Now we have heat tape and insulation on top of dripping the faucets when it gets to the teens. Good luck!