Yep - this happened to us too.
I cried and cried. I took my puppy to the groomers and picked up a stranger!! I was sooo upset. Only you (and others with the same experience) can understand. I'd share some pics - but Bailey wouldn't appreciate it.
I refused to go back to that groomer and found another one. Yep, she looked like a deer - its amazing how big their ears are when they are shaved
All that said - the good part is that we haven't had any mat problems since. I keep Bailey in a puppy cut with a bear face (love it!)- her fur is about 2 inches long and I dont have to comb her. She is the most adorable yorkie in the world!!
Please don't worry - it does grow back fast.