I am sorry your poor baby had to go through this. I don't think there is much you can do about it since there are no laws or regulations that effect groomers. There should be cruelty laws in your area but I don't know if they would apply here....though it should!
If it was a place that has multiple different people grooming the dogs it could be someone else got their hands on your little one this time or maybe someone was just in a hurry. I would have taken the dog right back and showed this to the manager and insisted on a refund. I also would have had a few other parting remarks including the fact that I would never return.