Poor service! They owe me $200!!!!

If i could, I would give them -5!! Terrible customer service as it has taken them more than 20business days to resolve an issue where they owe me $200. I rented a car through them, but when I got to the airport there wasn’t anything available. Middle of the night, STRANDED at the airport. They took my money and there is no one giving me answers, all they tell me is WAIT?? Until when?