I wish I lived near you so you could ride my colt! I had the exact OPPOSITE happen to me. I have a 3 yr old cow bred horse that I took to a reliable trainer (60 days). He started him in a snaffle for about 2 weeks, then moved his to a twisted wire snaffle with shanks and a curb, then, in the final 2 weeks moved him to a 2 inch ported correction bit! I was furious to say the least. Since bringing him home, I have put him back in a snaffle and a german martingale- he is working great with it...but the trainer said martingales and training forks are crutches
I agree with the others, send her to the head trainer and let him/her deal with it.