Shine - have a grooming ?

my mom recetnl;y moved here and and went to this groomer the first time, she did a good job, well my mom took her yesterday and a different person was working and totally shavd the dog, she is a shti-zu, my mom said she took eveything, off her beard, etc like a buzz cut and she is furious, she is going to call the owner, but how would you handle this being a groomer and what should she look for in finding a good groomer