The guys who made Blac Chyna a thing -- according to them -- are on the warpath to get a cut of her riches, and if they don't get it ... they're gunning for the producers of her reality show.
Jason Alston and Lincoln Hayes of Infinite Grind Multimedia sent letters, obtained by TMZ, to NBCUniversal, Ryan Seacrest Productions and Bunim/Murray Productions ... putting all parties on notice about their legal war with Chyna.
The duo says shooting, promoting, or airing "Rob & Chyna" only fattens her pockets and since
she refuses to pay them their fees ... they're threatening to add the producers to a potential lawsuit.
We broke the story ... Alston and Hayes claim Chyna signed a 10 year contract with them in 2007 and owes them at least $3 million in unpaid fees. They've threatened, but have yet to actually sue her for the dough.
Of course her employers would have no duty to pay BC's alleged management fees -- so, it's interesting they're attempting to drag the producers into this. Can't knock the hustle?