Termination by Employer

Hi...I was working for a reputed ministry. I was working as Consultant(Contractual) . I required 26 days leave for preparing my exam. I asked my senior to allow me leave. But he denied and said it is not possible.Admin officer advised me to go on leave as it is not a big issue.I was left with no option , I sent online leave application to my reporting officer and admin officer. They sent me a memo after 4 days and asked me for an explanation, I replied and explained my problem.In the meanwhile same officer provided 15 days leaves to 2 of my Colleagues.One of them want to go his hometown and other was preparing for same exam.I didn't get any reply from the organization after my memo reply.After my exam I called admin officer to ask him can I join office because I didn't get any reply.He said he is not looking matter anymore and asked me to talk to my senior than I again wrote a mail to admin to asked them what is their decision. When I didn't get any reply I again called admin officer and asked what's happening,why you people don't take any decision, he asked me to come and meet Section Officer. I went to office and explained the whole issue to him.He asked me to go and sit on my desk and report him if somebody asked me stand up from the desk. Really why do I knowingly let anybody to insult me but as per his suggestion I went and saw my colleague was sitting on my chair, he said he was ordered to sit on my chair. I asked Admin section officer to talk to my senior because they sent me memo after his orders. I waited for 2 weeks. Now yesterday they sent me termination letter and that by whatsapp not by any official email. Please advise me are they allowed to do that , can I take any action against them or are they correct?