I'm so sorry you had such a horrible experience with them.  The whole charade sounds like a total nightmare.  That is one good reason, I think, to avoid chain stores.  You never "know" the person who will be grooming your pet.  I go to a private groomer and can watch the entire time she is there and that is somehow comforting to me.  I will eventually groom Kacee, if she ever calms down enough  

 as I did Muffin.  It was wonderful for Muffin to not have to go through that ordeal, especially in her old age.  Good luck in your search for a groomer.  
