We just went through something very similar. My 13 year old DD came out of gym one night and refused to go back. 1 week before championships. I tried to discuss the issues with the HC (she was crazy, mean and cruel to my DD over the past 3 or 4 months) We moved to another gym, it is out of the way and she has to miss a bit of school, but the change is amazing. Great team mates, coaches who genuinely care and a happy, confidant young lady. I am proud of her decision not to be treated badly anymore. I can't believe I actually paid over $300 a month for the abuse she endured. I wish I had done it earlier. It was hard to leave the team mates as it was a small gym and everyone was close, but she is much better off.
I really don't think a meeting with your HC will change how your daughter is feeling or how she is being treated. All the best of luck to you and your DD