i'm gonna be real, based on what you've presented here she doesn't have much of a case at all. standing over someone's shoulder saying "that sounds cool" doesn't give someone producer credit on a song.

seems the guy was capable of producing these songs for some time after cutting ties with her, which is not surprising because vocolioid songs were pretty hip rage for a few years prior to the post date of the big hit here.

anyways not sure where this guy is slandering this girl, the only potential slander i see is this video, and this is literally the only i've heard of it or can find of it.

it's not that i don't believe there wasn't some kind of falling out, but i just doubt that she has much of a claim on credit for the music. she'd have better luck going after compensation for use of her image in the branding and marketting of the music that is still ongoing, but you know through legal channels that have a real chance of getting something done here instead of this.

it would also build a more compelling case for your claims if you produced some music on your own. if all she did was have an idea that doesn't mean much when it comes to production credits really i'm sorry to say, until she produces those ideas herself. and maybe she's got some genius production ideas idk, i don't know because i don't see any music she's produced herself presented anywhere. i just see a video of her claiming this guy stole her ideas amongst other claims that seem to mutate as you post more and more.