Chief Keef screwed over breast cancer patients by bailing out of a Cleveland charity concert hours before he was supposed to go on stage ... according to a lawsuit obtained by TMZ.
In court docs, Kim Productions claims it paid Keef a $15K deposit ... to perform at the RapCure cancer benefit last June. The balance -- $10K -- was supposed to be paid at the event.
Kim Prods. claims the day before the event, Keef demanded a $2,500 advance to cover travel expenses. Kim says the money was wired ... and Keef's agent claimed Keef was on his way.
According to the lawsuit ... Keef was a no show ... so the concert was cancelled and ticket holders got their money back ... which meant the charity ended up in the red.
The company is suing for $26K -- the money it paid to Keef plus the amount spent on the theater, lights, equipment, advertising and the refunded tickets.
It also includes an $88 charge for an order of chicken wings ... called in by someone on Keef's tour bus.