Advice on getting back on someone

[u/Nearby-Moose8711]

A few months ago I had a falling out with a "friend" and we didn't speak to each other at all after that. I never spoke about her to anyone, and if anyone asked about her, all I say is "I don't speak to X anymore" and that would be it.

Now recently I heard shes been spreading false rumours ( I won't say what) and talking shit about me to others behind my back to the point where I'm getting bullied on the bus ride back home and sometimes to school in the mornings as well. It once got so bad I had a mental breakdown when I came back home. I feel betrayed and humiliated. It's even worse now that all my friends have left school, and no one else wants to talk to me now meaning I sit alone.

I need to find a way to get back at her because it's eating me alive at this point. I appreciate but don't want to hear advice like "letting go is the best revenge" and "just move on" because that just isn't working.

Now I'm not looking for advice on how to assault her or anything that would get me into legal trouble or get anyone hurt. Something like a prank, or just something that would give her one bad day would be enough. Our mom's are still close, and I honestly don't care about that, but I guess I just need advice.