As per my knowledge no one can terminate an employee without any issue / reason. Forget about it if the employer / GM has inform you leave the organisation, put a mail to him asking the reason while marking CC to your HR Head. As all company need to follow the due process of law, you will get the appropriate reason while doing so.
For workers and employees the law is strict and they can go to labour Court. For supervisory persons they will have to go to Civil Court.The maxim "wherever there is a right there will be a remedy " will strictly apply.
Please do not tolerate this nonsense behavior and ask for the reason.Please take this matter seriously and take required step regarding the issue.No one has authority to fire you without any valid reason.Keep informed everything to management and even though nothing is happening then approach civil court.