Asking to change job profile or doing termination

Hi, I explain my case for consultation as how can I proceed with law suite to my company: 1. I gave interview and the Job profile offered is Development. 2. I cleared all rounds they gave offer and then I joined company. 2.a. Offer letter don't have any terms and condition, just offer of salary and designation. 2.b On first day of joining they provided appointment letter and asked to sign terms and condition. I signed as I already left my company. 3. At time of interview they said they have many projects but when I joined then found they have only one project. 4. They had said for first 1 month that requirement will come, but after one month they said other project manager will take you for different job role i.e support. 5. I asked for this I have not joined the company, then they said either join this or leave job. My question is: 1. Can they put you in different job role If they promise other Job profile . 1.a If they do not have requirement then why they hired me, if they were expecting some requirement and that don't come then can they spoil my career as per their will, i.e isn't its their responsibility to take care me. 2. Without giving me any working opportunity can they fire me with this reason only that I should work whatever they say, means if they say I should clean toilet then should I accept that or sue them for spoiling my career. 3. Isn't this a mal-practise for playing with anybody future to hire him just they expect some requirement and didn't materialised, means they should mention this in offer letter that your employment depends on this requirement i.e if it comes you stay else will be relieved. 4. I am having home loan on me is a big liability. This is with Software company in NCR and I require consultation as how the case can be and how can I proceed. Thanks and Regards, Software Consultant