How long will it take my Keeshond's hair to grow back?

We took him to the groomer to be washed, brushed and groomed. There was a new owner. We told her we liked the way the previous owner always did a good job getting any tangles out without shaving our dog. Later my husband went to pick up the dog and found that he had been shaved. His fur is now 1/4 inch long! He does not look like himself at all. He looked like the dogs you would see on calendars before he was shaved. What can I do. They didn't even call to ask us if it was okay for them to shave my dog! If you have ever had this happen please let me know the results.