I am so sorry it happened to you.
I completely understand you! I also grow Maxi's hair and it just takes a while so I think I would be very pissed too! I keep on seeing that a lot of people say that Petsmart and all those commercial places are filled with bad groomers. I never used them but heard a lot. It is hard to find a very good groomer who understands how you want your baby's haircut. I was lucky enough to find one who takes only one dog at the time by appointment. My baby is always done in 1 1/2 hours which is awsome. Other times I just trim him myself.