1. Do not succumb to her blackmailing tactics. She seem to be a crook and she must be stopped at all costs.
2. Whatever she is doing are all unlawful and punishable offence under various provisions of IT Act and IPC.
3. So lodge a complaint of blackmail and cyber offence with the local police and the cyber cell.
4.once FIR is registered agaisnt the girl all your problems would be solved.