The service rep "Mike" didn't seem to want to stay...

The service rep "Mike" didn't seem to want to stay to complete service. He ended up doing the work, but after he left, the furnace no longer worked (it worked fine before he arrived). I found out a couple days later after we got home from an out of town trip. Fortunately, they were able to get another rep out to fix the problem. Apparently he installed some electrical part correctly, but didn't adjust it so that it would function. After the new rep corrected this, it seems to be working fine.