Current Company Refuse to give NOC

All you can do is negotiate with them.

Sometimes companies can be annoyed when they suddenly find out an employee who they have spent a lot of money on bringing into Malaysia is "jumping ship". But you cannot force them to issue the NOC and you definitely need it.

But if they dont provide me NOC then do i have the option to go back india and come back with Approval letter?

You have to get your current work permit cancelled and your present employer has to do that. You need that and a NOC letter.  So you do need their cooperation.

You could only accept another job once your current work permit expires (remaining in India while it is processed).

If they cancel my EP and not give NOC, then do i have the option to go back india and come back with approval letter?

If your EP does not expire  naturally, immigration are going to ask for the NOC.

Apologise - try to understand their position - check your contract of employment to see if you have to repay anything to them for leaving......

Sorry but don't listen to Gravitas. He is one-sided and in favor of the employer.

Even though your employer have spent effort in bringing you to Malaysia, it is still your right to jump ship. Otherwise, it is slavery.. Also, your employer is not the only one who exert effort but also you. It's not that easy to work abroad. You have to leave your family.

So the correct solution for your problem is to go to your embassy. The embassy can sue them for "enslaving" you or blocking your right to find another employer. It's illegal for employers to halt the release of the employee if the employee has no other obligations to his employer.

The embassy can take the case to the Immigration and they will help you to on your Release.