The chain on the opener has come off. How do I fix this. Or how much will it cost to have someone to come out to put it back on. I am in Ontario canada.
You can loosen the chain at the trolley and put it back on the sprocket. This is not a normal problem and is caused by something else. Most usually the bearing supporting the shaft the sprocket is on is worn and lets the shaft lean. I can't help you with costs in Canada.