Keshia Knight Pulliam Sued -- You Make a FORTUNE on 'House of Payne'

Keshia Knight Pulliam made $20k PER EPISODE to star on "House of Payne" this season ... and then fired the agents who put the deal together ... this according to a new lawsuit obtained by TMZ.

KKP is being sued by Greene & Associates Talent Agency ... which claims it signed Keshia back in 2007 and immediately got her a lead role on the Tyler Perry TV show as Miranda Payne.

G&A claims it kicked ass for KKP, getting her between $7,500 to $20k per episode ... including $20k per ep for all of the 2011-12 season ... not bad.

But not good enough for Keshia ... because according to the suit, she fired G&A back in July.

There's just one BIG problem ... G&A claims Keshia never forked over a single cent in commission from the 'Payne' deal ... and several other shows it worked on for Keshia.