Hi Baiju,
Can understand your feelings! After working for almost 7 years now, you have been neglected and they have not given you whatever they had promised you earlier. Their attitude has changed towards you and they are asking you to accept the present terms or quit!
Since I am working in senior management positions all these days, let me express my views without taking any sides! Please take it in in the right perspective .
You are working since 7 years and you had been promised so many things , that too by a foreign contractor firm. It is the normal attitude of any organisation, that if a person who is working with them for long periods is not productive nor is counter effective in their future growth plans, they will try to find a way to get rid of him. The easiest way is to deny all that has been promised to him like increments, confirmations, benefits etc., so that the person gets frustrated and leave the job. This is the normal practice. You may be a senior person and working honestly and to the best of your abilities but your management may be thinking that you are not fitting in their plan of growth. They may be expecting something more from you which probably you only can understand! I personally feel they might have dropped hints in the past about your non suitability in their scheme of things.
Please do not get frustrated. The long experience is behind you. You can definitely get a better job with better compensation package.
I really don't know by giving my views, whether I have hurted your feelings! If so, kindly forgive me.
If you want a format of resignation letter which expresses your views, your feelings , I may draft a letter for you once I know your feelings/views expressed in this posting.
-Srinaren