Im furious.. just ran into someone who told me she heard that my relationship ended because I lied to my ex. The only one who could have told her this would have been ex (since it was a specific circumstance she was alluding to) I'm pissed because I didn't lie, am not a lier, and why my ex would still believe this or spread false stuff about me. I'm not sure what to do, I want to email her and tell her to stop this (and ask her to not reply as I don't want to talk about it/hash old things up) I honestly could care less what she thinks about me at this point, but won't stand for being accused of being something I'm not.
Should I or just let it go? I haven't talked to her in couple months and could care less if we talk again so this isn't a ploy, just want to stop this spread of false crap.

You have no control over what she says, and does, nor should you care.

Let it go, and don't get into her drama.

If you contact her it will only be adding fume to the fire and now then she might spread more rumors.

Leave it alone and when it comes up you have the right to defend yourself against the lies. As Tal said "move on".