This escalates into the destruction of her hearing aids, and the administration is called in. Ishida's coconspirators sell him out.
Ishida's mother pays Shoko's mother for the hearing aids, and (it seems) takes physical punishment as well.
Ishida becomes the target in class.
Things escalate when he catches Shoko cleaning his desk. (Removing some nasty remark.) They get in a fight.
Shoko transfers to another school.