Hello, i would like to know about my situation, i...

Hello, i would like to know about my situation, i rented an appartment in a place that used to be a hotel appartment but now it's just appartments, it's in abu dhabi, i first found this place on an application (dubbizle) i called the advertiser and came to see the appartment, he wasn't the owner, he claims he's an agent, and he asked me for 5% commission on the annual rental, eventhough it's a monthly rental and im only staying for a couple of month, i didn't take the deal, and after a few weeks i called the place and not the agent, i asked them about the details and the price, and i asked if their are any agency fees or any additional fees, they said no, so i came back and i signed the contract without any additional fees, suddenly after i rented the appartment this agent happened to see me walk through the building, and he is telling me to pay him his fees and i dont have the money for that so what can i do?