I wish to share the expert's suggestion I received on this case:
"The act performed by the person is not cyberbullying but is beyond cyberbullying. Cyberbullying is a general term and has no specific legal value in a specific context.
Legal Recommendations
I recommend that the person who is defaming the company be handled not only under cyber law but also under IPC and CPC sections. Ideally, I recommend that the person who has maligned the name of the company be tried for defamation under IPC and CPC, and also for issuing threats (if any) and/or criminal intimidation (if any). Defamation is a very serious offense, and if dealt with properly, it can generate very serious and positive results.
Steps to Take
The company has to approach the Police Cyber Cell and seek their help. The company, through authorized government officials of the cyber cell of the police, should try to find out the traffic that this particular person has been able to generate on this website/account on Twitter, as this will help the company somewhat ascertain the damage caused by the person's defamatory posts against the company.
There are many Cyber Forensic experts who can help you locate the exact location, both current and past, of the person who posted the defamatory materials against the company. Also, the Cyber Forensic expert will help in collecting data on this issue and will help in strengthening the case when represented before the apt courts.
The matter has to be dealt with in a mature and serious manner because he is maligning the name of a company via social networking sites, and God forbid if these details reach the company's foreign clients, then they might even discontinue their business with the company."