First of all thank you for bringing this up. And not just sitting ideal like many people do!
The previous reply by Ms. Saura Patil has wonderfully explained the substantive laws associated with this issue. I.e. Sec 354D (criminal law (amendment) act, 2013, Sec 509 (Indian Penal Code) , and Sec 67 (Information Technology Act) can be initiated against the person.
These are the provisions which can be used against the perpetrator. But to make things swift, please file a complaint against this person on all/any of the following portals (only to escalate the issue and bring it to the notice)
1. File a complaint on cybercrime.gov.in
2. Dial 100 and state your matter. (You can site the above sections if they do not agree to file a complaint)
3. Any nearest police station. You can site the above sections if they do not agree to file a complaint)
If she is not willing/afraid of the police/court then,
4. NCW (as stated by Ms. Patil) can also be mentioned on thier twitter account.
5. Can state your problem and issues on cyber-crime help webpages like 'cybersathi' 'akancha against harassment' etc.
I hope this helps!
And kudos again girl. All the best. Please do update me on this on firstname.lastname@example.org.