Offer of Possession without Completion/Occupancy certificate

Dear Sir/Madam, I am looking for some solution in a property issue where the builder had given us an offer of possession in Dec 2015 without having a completion/occupancy certificate. We refused to take the possession without completion/occupancy certificate and asked to provide the same only with CC/OC. Since then the builder has stopped responding to my calls and email. Please guide the best way out. We are currently in a 'Wait and Watch' condition. As per the information sought from some sources, though applied for CC/OC there are bleak chances of receiving the same in near future by the builder owing to its faulty practices and excess construction. I am a middle class salaried person with limited source of income. Please guide me through the best and cost effective resolution. Is there any way to go to consumer court or legal notice or anything else. Request you to suggest the detailed way to get out of this problem without paying any interest on delay in payment as per the offer of possession. Till now, I have paid all instalments on time except the final offer on possession. Regards, Rishi