Builder Owner contract Agreement violation

Dear Sir, We have a land and we had given it to a builder for developing Apartment. All the investment will be done by builder and inturn he is eligible for say 40% or 50% of the Flat. The builder has begun construction work but is not completing even after 6 years. His commitment to complete the project was 3 years. Now the problem is neither he is doing construction in full swing nor he is giving any money to us. What can we do? What are options, legally, we can factor in to resolve the matter or get rid of builder. Waiting for the reply. Thanks