I had a technician come and charge me $500+ as a deposit for replacement of a part that needed to be ordered. The company called the next day and said the part wasn't available, and backed out of the project. However they are keeping $260 + HST (the labour costs to replace the part) as those are non-refundable according to the contract.
The reason is that the fine print in the contracts says that any labour costs you are agreeing to are only for whatever they have already done that day, so you owe them 100% of the labour even if they never do the project.
If for some reason you do decide to work with these people and they need to come back another day to finish a job, make absolutely sure before you sign anything that they can actually do that job. Because if for some reason they can't do it, they will still charge you 100% on the labour.