The Maverick aired his frustrations on social media just minutes ago ... claiming his drink company is "under attack" by false narratives being thrown around on social media -- and it's time to take action, with King Ryan being the first on his list.

"Today we begin to hold those accountable who’ve damaged our brand for attention while we correct the narrative," Paul said on Instagram. "We're here to stay and will continue to change the world of hydration with bold flavors and creative innovation 📈."

In the lawsuit, obtained by TMZ Sports, Prime lays out Garcia's alleged wrongdoing ... pointing out his social media rants about how the drink will "kill your guys's (sic) brains," "mess up your guys's (sic) liver," and "hurt you big time" among other harmful side effects -- without supporting the claims.

In fact, the lawsuit points out how Garcia alleged Prime contains "ostarine" -- the banned substance he tested positive for in relation to his Devin Haney fight (side note: Haney is a Prime-sponsored athlete).

Prime claims Garcia is damaging its business with his posts that allege the company is linked to the devil and its employees have "raped" and "burned" children.

The lawsuit states Garcia is well aware his claims are bogus ... but is spewing the nonsense to promote his own brand, which is based on stirring up drama.

Prime is suing Garcia for defamation, trade libel, violations of Lanham Act, unfair competition and unjust enrichment.

Of course, Logan and KSI's Prime has quickly become one of the most popular drinks on the planet ... with the company adding Patrick Mahomes, Terence Crawford, the Los Angeles Dodgers and Lakers, Erling Haaland and more to its growing list of sponsorships.