1) you will have to move civil court in this regard . you have entered into development agreement for development of your plot for commercial purposes . hence consumer forum wont entertain your complaint .
2)is the developer an individual or company ? . better enter into development agreement with company . if developer is one man show you would get stuck as his legal heirs may not be interested in completing the project . in case of company the project would be continued by the company even if one of the directors die
3) get the development agreement drafted by a lawyer