AITAH for sending a singer a legal warning before suing her?

I (17F) am writing this on behalf of my mom (54F), who is a songwriter and worked on a song with a producer, and a singer I’ll call Vanessa recorded vocals for it, but there was never a signed contract between them.

The original plan was that Vanessa would buy the rights to perform the song for €700, but my mom actually wanted to help her because she has an ill child, so she was willing to lower or even waive that amount, and because of that they didn’t finalize a contract yet since the payment terms weren’t settled and a contract would have made it necessary.

Despite that, Vanessa started posting teasers of the song on social media like Facebook and TikTok and even uploaded a full music video without getting permission from the actual authors, and she also didn’t properly credit my mom or the producer.

Eventually the video got taken down after pressure, but she continued publicly making claims that weren’t true and presenting the situation in a misleading way.

For context, my mom paid around €300 for recording and production, while Vanessa paid about €300 for the music video, so in total €600 was spent on a project that ultimately fell apart.

Also I was playing in the music video but at one point Vanessa got jealous of me because (by the script) I was supposed to be acting alongside young guy on which she put her eye on (he has a girlfriend and is 11 years older than me) so she started insulting me privately to him (he showed me every text) and than she even went so far and told the producer he should not be helping me in becoming a singer myself because by her words I don't know how to sing which is false because I've been told by singers, musicians and professors in that field.

After everything, the situation escalated even more because Vanessa started insulting my mom and people around her (me, my friends that we're present during filming and the producer) publicly, calling them things like pathetic and evil, and she also made really serious accusations saying my mom is part of a cult just because she is a Jehovah’s Witness (I know myself that they do look as a cult in some ways but they didn't, don't or won't hurt anyone in ways the singer described because they're against violence), and even went as far as calling her a witch and claiming she does blood rituals, which is completely false.

At that point I decided to send her a formal legal warning asking her to stop using the song, remove any related content, stop spreading false claims, and that she takes me out of the music video because she didn't go by the script and deliberately made the scenario to be such so it makes me look bad, and I made it clear that if she complies we won’t take further legal action.

She has ignored the warning and continues acting like she’s the victim in all of this, and to put it as politely as I can she is being a crybaby about the warning and instead of messaging me she went to the producer to so to say "cry", so now I'm seriously considering filing a lawsuit.

AITA for escalating this legally instead of just letting it go?

Edit: I saw that some people got me wrong, so to clear things up I'm not looking for law advice since I'm very informed about everything, I'm purely asking if I'm the AH for wanting to sue her if she has an ill child.