Club Factory — about lucky draw

We got a message about lucky draw of winning 4.2lakh...Welcome to CLUB FACTORY shopping Pvt Ltd.co
Dear Sir,
Congratulations! You have been selected as a 1st prize winner in our yearly Mega Millions lucky draw and you have won The Car "MARUTI SUZUKI ALTO" or The market value of car Rs.420000/-. For the service Registration charge Rs7500/- and The
TR paper charge Rs8500/-
For more details contact our helpline No.[protected]
they asked for 7500/- we paid for two times to two different persons they said they will pay quickly within 2mins later they are asking for 16000/-two people did the same.. later they are not responding...we lost 15000/- what we should do now?we want our money back plz help me..we paid 15000 now they are asking for 16000 as gst fee to receive money..what should we do?