Ring (519) 878-7776. You get me, not a switchboard. If I am on a job I will ring you back, and I will tell you roughly when.
If it is easier to type it than say it, text the same number, or email mozeegas@gmail.com. A text with the make of the unit and what it is doing is often enough for me to tell you what it is likely to be before I set off.
Do the safe thing first. Get everyone out, do not touch the light switches, and ring your gas utility's emergency line from outside. They come out at no charge and they will make it safe. Then ring me and I will put right whatever caused it. There is more on that on the gas leak checks page.
My Google listing says open 24 hours, and no-heat calls in February genuinely do not keep until Monday. Ring whenever it has gone wrong. If it is the middle of the night and it is not urgent, leave it with a text and I will come back to you in the morning.
If it is easier than ringing, put it here and I will come back to you. Tell me what the unit is doing and I can usually say what it is likely to be before I set off.
London and the surrounding area. If you are just outside it, ring anyway and I will tell you straight whether I can get to you.
London and the surrounding area. Just outside it? Ring anyway and I will tell you straight whether I can get to you.
Installation, repairs and service on all of it, tested before I leave.