Naaptol Lucky Draw Scam — fraud call

I got prize coupon for 2.5 lakhs. I sent prize code to the number which number is in coupon. I person named as baskar call from kolkata, he told, "you should pay rs. 3500/- for processing charge". And i paid that money. Next i got sms from panjab national bank in that"your transaction is on hold due to 3% (7500) gst is pending". After that i paid rs.7500/- also. But i don't get prize money. After next day i got sms again from panjab national bank.in this time, they told you have to pay cgst-3%. (7500). But i told i can't. Refund my amount. But they are not response.