The former couple shares four-year-old King Cairo, but according to Blac, the Rack City hitmaker has not been paying his dues to help take care of their son.
Blac took to Snapchat on Wednesday (29Mar17) to vent about their personal problems in a series of expletive-ridden posts, claiming she can finally see the "funny" side of their 2014 split, when Tyga allegedly kicked her out of their home and left her "2 grind from the dirt".
"And they wanted to see me fail! lol (laugh out loud)..." she wrote, adding, "No child support!"
In the rambling outburst, she goes on to allege Tyga, real name Micheal Ray Stevenson, has even stopped paying King's babysitter Jenny, before suggesting he is using his current girlfriend, Kylie Jenner, the half-sister of her on/off fiance Rob Kardashian, for her fortune.
"Stop running to ur money! Telling my business about King!," she continued. "I bet any money! I got more money then ur account Tyga, Michael (sic)!!!
"So go tell Kylie, and Rob! About our son Account! Cause that's the only reason I'm contacting ur f** a** (sic)!"
Blac, who is also mum to four-month-old daughter Dream with Rob, ends the rant by blasting Tyga as a "b**ch", and challenges him to confront her in person at her Los Angeles beauty salon.
Tyga has yet to respond to the allegations, but it's not the first time his finances have come under scrutiny.
Last year (16), he was forced to pay a $208,330 (£168,000) settlement deal relating to a long-running jewellery debt with bosses at Jason of Beverly Hills, while his luxury Ferrari 488 sports car was repossessed in November (16) after he reportedly failed to keep up with lease repayments.