Infoedge — job placement scam

Address:

New Delhi, Delhi

So there is this woman called tania (Phone no. +[protected] who says she's calling on behalf of naukri and wants to give you a job. She asks for 2500/- for the same.
My sister (Whom she made the call to) refused this service to which tania said that now you have to pay a challan for refusing the service! The audacity, my god!
She is threatening my sister of 'see what will happen'. How can we round up these frauds?