Booked in a Project 2 Yr Back In Pre launch Offer construction delayed

I have booked in a project 2 years 5 month back. As per developer construction work was expected to start within 3 years. But it has not been started yet. Whenever I go to their office for updates of the project, they told that some government clearances are pending. As per terms mentioned in allotment letter booking amount has been locked for 3 year, if it is with withdrawn before, 15%of booking will be deducted. After 3 years money can be withdrawn with 12% annual interest for three years. For this company has given me an instrumental check with Sum of booking amt. & interest in 3 years later dated. Now I have dought that developer may not return my money. Because company website and email id is not active now when I search or mail. How instrumental check works. Shall it be valid after 3 years. Should I wait for seven months to complete the lock-in period or I can take action right now.