Termination without valid reason

The company Ernst&Young (EY) issue termination letter without valid reason. I asked them to change my work schedule on medical grounds. Since the company works in two shift timings, I asked them to change it to 11 Am (it was 8.30 AM). I did this due to medical reason.Also have submitted all the medical documents. After meetings and discussion, they said you are required to report at 8.30. When I used to got bit late, they used to mark my half day. Then I had stopped going and exchanged emails requesting them to change. I had severe gynea issue. They issued me termination letter without prior notice and disable my laptop and other It related service on 10th May 2016. 1) They did not issue prior notice. 2) Initially harassed my by not providing cab and not intimating during interview. That was HR team’s fault 3)Issued me appointment letter after aprox 1 month of my joining. 4)No one in the company responding to my calls and emails. Globally and in India. Escalated to CEO level. They have done one way communication. Given lots of emails and calls to everyone in the company. No response now. Please advise. How can they do this without prior notice. I am having my house loan.What should I do now. Spending sleepless night. Rgds, Jyoti