Refused to give back deposit

The house is beautiful and the landlord communicates well until you move out. I shared this home with 2 other nurses. We gave a 30 day notice. We had an outside contract from Furnished finders. $2900/month and $500/refundable deposit. We deep cleaned and left the home in perfect condition. All linen, rugs and furniture covers washed included. All appliances cleaned. Everything was perfect. However, we did not power wash the garage. It wasnt dirty. We did not have a cleaning deposit, yet the landlord decided to keep our $500 refundable deposit and wont return it. We even left 3 days early even though it was paid for. Just another landlord taking advantage of nurses. I have requested the deposit many times. I have contacted furnished finders and they informed me to write a review to warn other renters. $500 might not be a lot to some, but its still $500 at the end of the day.