Intake manifold gasket replacement

A week or so ago, I had the intake manifold gasket replaced on my 1997 5.7 liter V-8 C-1500. The garage replaced the serpentine belt tensioner with the claim that it was a good thing to do because the OEM tensioners fail and, horrors, go into the radiator. It seemed like a good reason. However, the job has turned into a nightmare. The timing was not set properly, so a warning light came on and they worked on it four hors to set the timing. It's anybody's guess if they did it properly. Then yesterday, I smelled gas, pulled over, looked under the hood and saw the top of the intake manifold wet with gas. So, the garage sent a wrecker to tow it to find and fix the leak. Could have been really serious. Any comments?