I know a little of how you maybe feeling.
I had a situation with my daughter and her school not undestanding her needs and blaming her for incidents in the classroom when at times the situation wasn't her fault, sometimes she was to blame, but because her behaviour and reaction to other children teasing her caused mild temper tantrums she was labelled a troublemaker , which encouraged her classmates to tease her more to get a reaction, knowing full well she would get the blame and the teachers would not listen to her or me.
She is doing very well now, but the incidents of her early school life have scarred her and her self confidence is not high.
I didn't speak up enough and allowed myself to be led by what they (teachers) thought what was best for themselves IMO and not really the needs of my daughter.
I hope you get this sorted and don't let the teachers make you feel you are being difficult, your son's welfare is more important than a teacher making a "victorian" measure to stop your son from forgetting his tokens again, there surely are better ways to help him, than have him ridiculed.
God Bless