I took my bike for gear shifting problems. I got t...

I took my bike for gear shifting problems. I got the call around the time they said it would be done (~3 weeks nowadays). Went to pick the bike the next day. Didn t get a chance to talk to the person whoever serviced the bike. Paid for the service (~$64) and took it out for test ride. First time I tried switching the front gear, the chain came off (one of the problems I told them to look at). Took it back, one of the service guys apologized and took it back in the shop. Brought the bike back in 10 mins or so. Tested again and this time worked fine. I will take the bike for a long ride tomorrow. I wish someone explained what was done and if there were any future suggestions.