I had this issue today. Heck of a racket when a spring breaks. I used Ace Garage Door Repair.
www.acegaragedoorcalgary.com
I was fortunate that Jason there was nearby and he was available same day. His pricing was reasonable, 260. Door House didn't call back, Crosstown was looking at Tuesday after the long weekend and about 20 higher.
He also had some recommendations about maintenance and things to keep an eye out for. I was pleased with his work. He invited a call if any issues were to arise.
(Also thanks to CP for flagging that scamming sleaze. Even though the thread is a couple of years old, it's good to be able to easily avoid that.)