Bonding causing sensitivity, dentist blames my brushing

I've never had problems with my teeth, except for minor gum recession. The dentist told me that bonding would help with the sensitivity, and I'd need to brush more softly. I adjusted my brushing SIGNIFICANTLY, but now the sensitivity is worse than before, extremely painful, and he dismissed me by saying "you’re brushing too hard, the bonding flicked off" and told me insurance would not cover the fix. The feeling is unbearable and he will not help me. What do i do now? Thank you!