Overnight Express Courier - Booking amount not returned

I talked to a military cisf personnel in jaipur airport who wanted to sell his furniture ànd electronic items. He asked for booking amount of **** which I paid , but right on the day of delivery he asked for more money stating that airport transport service won't deliver if I fail to pay gst amount. I told him that I will pay after the delivery. He said no. Now I want my booking amount back. After asking him repeatedly he refused to make payment.