ROCK SOLID AUTO CENTER Sold me a car and then repo'd it 3 weeks later demanding more down payment and now they won't give me my $500 down payment back Mesa, Arizona

I bought a car from Rock Solid and 3 weeks later, with no warning, they repo'd the car and demanded more money down. Come to find out they screwed up and had not even secured financing yet, but they were trying to get more money out of me. The deal did not go through and when I contacted them to get my $500 down payment back, they refused to give it back. I am currently in the process of filing a lawsuit against them and I have reported them to the Attorney General's office to investigate. They are very unprofessional and crooked!