Section66A of IT ACT clearly defines the Punishment for sending offensive messages through communication service, etc. as under:
Any person who sends, by means of a computer resource or a communication device,—
(a) any information that is grossly offensive or has menacing character;
(b) any information which he knows to be false, but for the purpose of causing annoyance, inconvenience, danger, obstruction, insult, injury, criminal intimidation, enmity, hatred, or ill will, persistently by making use of such computer resource or a communication device,
(c) any electronic mail or electronic mail message for the purpose of causing annoyance or inconvenience or to deceive or to mislead the addressee or recipient about the origin of such messages
That person shall be punishable with imprisonment for a term which may extend to three years and with fine.
AND out of this section Section 144, IPC, 1860 is also there to punish the accused.
Prepare a police complaint against that lady after narrating all the facts as you have written here along with the said proof/cd and calls details and lodged an FIR against that lady immediately.
If, police not ready lodge FIR ,then forward this complaint to higher police official.
This is for your friends safety purposes , otherwise tomorrow she will blackmail him in future.
Good luck and dont forget to Rating