Lil Scrappy -- Concert Promoter Stiffed and Humiliated Me

Lil Scrappy says he was left with no money and no roof over his head after a concert promoter screwed him over ... on a messed up night that culminated with police intervention.

Scrappy tells TMZ, he was scheduled to perform at Club Vizion Sunday in Louisville, KY, but when he showed up to do the show -- the promoter didn't have the money to pay him ... so Scrappy refused to take the stage.

Crowds of people had already shown up for the performance -- so Scrappy says the club owner paid the rapper a small sum to do a meet-and-greet instead of a show ... and Scrappy agreed.

When all was said and done, Scrappy says he went back to the hotel the promoter had arranged for him -- but the hotel informed him his reservation had been canceled and he was required to vacate.

A source at the hotel says cops were called to assist in Scrappy's removal -- but the rapper says he left voluntarily.

Scrappy tells TMZ, he has no plans to sue the promoter -- but vows never to work with him again