One problem with every repair shop I worked at was the balance of manpower vs. work. If it is well-manned for busy times, there will be too many techs paid for nothing in slow times. So they under-staff, promise a three day estimate to be competitive , then get more work than expected and run behind. It's a fine line to walk. I could go on for hours about this stuff. I once had someone approve an estimate "but only if it is done this week". So I didn't look at any new stuff for a day and a half , got his TV done (it was a tough one, multiple problems), called the next day and he refused to pick it up saying "it can't be worth what you're charging if that's all the time it took".
So I guess I'm suggesting to hope for the best, they don't get paid and need to find a new job if they don't actually do the repairs, so it is in their best interest to actually do their jobs. It just might not seem like it on the outside.