Job.

I am a senior merchandiser working in export house for 17 years. Recently I changed my job and joined one new company. I got an offer letter for Sr PD merchandiser. But after joining, surprisingly, they assigned me work which was slightly different in profile. When I raised the issue, they said we needed person for this profile only and blamed it to some goof up between their two offices branches. Though I did not like it. But took it as I had no other job option. I was trying to settle down and was doing all the work in hand with full sincerity. But to my shock, with in 15 days, HR manager called me and said you are not performing and you are no more required. Point to be noted here is, no one showed any amount of dissatisfaction with my work, during the days I worked. I ask them to explain my non performance, but they have no answer. There is one guy whom I was suppose to report. I feel he is the man behind all these. He is doing it because of some internal politics of the company and he wants to settle some score with somebody. My question: Is there any possibility to sue them for mental harassment, As I am really feeling depressed due to this incidence. Or else what can be done.