It is a good thing that when you or your dog gets a bad hair cut that the hair does eventually grow back. I would never return to a groomer who does not respect the request I have made concerning my pet's grooming. I bring them there for a service that I am willing to pay for. However, if they take my pet and shave it despite the fact I asked them to do something differently then they will never see me or my pet again. You should be able to discuss with the groomer what is to be done in advance. If the groomer has an issue about your request then they should mention it at the time you bring your pet in. There are also things called cell phones that they can reach you with if somethings comes up during the grooming.
The real issue here is that many grooming salons are full of people who have very little training, skill or experience at what they are doing.

I hope you are able to find someone who will respect your wishes in the future or maybe you can get the equipment and some training to groom your beautiful pet at home. Best wishes for your future grooming experiences.