Potential customer threatened to sue me

Hey y'all!

So long story short i am a college student in my first year trying to create a SaaS side hustle.

A few weeks ago I got this idea from a friend, he paid a guy to copy his competitor’s blog posts, to target the same keywords and topic but change the wording so it won’t be copyrighted.

I told him that i can build a software to do that task even better than the guy he hired and i created Seoheister - https://seoheister.com . Basically it gets a blog post, extracts the important information, then it extracts the keywords that it should rank for, then rewrites the blog is a way that is similar to the initial one but it gives it a better wording, and more exact targeting on those keywords. That way it keeps the informative and human aspect but it ranks better.

Fast forward the mvp phase, i started to cold email some other companies, saying something along the lines of your competition outranks you in these categories and this is how you can quickly fix it.

Everything went great, until i woke up with an angry email response, saying that what my SaaS is doing is wrong and I shouldn’t copy other people’s work and that if i was to continue working on my project he would sue me for copyright.

I am not scared because of that, I don’t think it has any grounds to do so, it is just a tool and people chose to do what they want with it but i am not sure if the idea is worth pursuing even tho i have initial traction, because what if that guy actually has some grounds to sue?

Just looking for some advice.