One time I put a tarantula i found in my bullys bag. The bullying from that guy dissapeared the very next day.
But I dont think thats very good advice. (Maybe bugs aint your better side, idk)
Try going to one of your teachers, or principal to report this behaviour from the other party of students. Maybe its for the better if they get called out, and get their parents called. If the school is not helping, there is an app that can record your whole entire day on audio recordings. A guy in my school pulled this trick, it was amazing to watch.
I am unfortonately not here to give you advice like "just ignore them" or "walk up with your head in the air, you are a girlboss1!1!1" im here to give you some advice that may work in the real world, because I first hand experienced bullying like yours. Ignoring isnt gonna help, you are maybe even gonna get shoved down the stairs becase you pissed some guy off because of it. ( sorry mate, it happens), but I prefer calling the parents number. Most parents feel ashamed of their child for being loud in the class, let alone bullying and spreading lies about another child. Just be an angel infront of the parents, tell them the problem, and it may juuuust work perfectly.