and your NOC is addressed to the third employer?

You filed your resignation when?

The reason why an employer has your passport is to proceed with the visa transfer. They maybe waiting for you to had over the NOC for them to take the next step.

BUT...you went and accepted another offer from another company???? TSK TSK TSK.

You are in a rut because you did it to yourself. If I were the second employer, I'll have you pay me back for the expenses(visa transfer fee, salary...etc).