You can fix just about any part on your furnace.
The reason the hvac companies have a racket going is because there are some dangers to be concerned about.
I know here in Colorado we had some deaths because of simple exhaust pipes not being put back together properly. That changed all our codes and I believe we are legally supposed to have a licensed professional do any of the work involving gas appliances. On any of the homes I build, I won't touch anything of that nature. but on my own home, I have no one to kill but myself and my wife, so I fix everything when i can.
Most any company will over night ship anything you want. So all you really have to do is find someone who will 24 hour ship. The usps offers next day 10 o'clock to 12 o'clock for an extra 5 bucks. Oh, your in Canada aye. So maybe it's not that easy for you??