1) issue legal notice to company to deliver plots in respect of advance payment was made . offer to pay balance amount payable as per your agreement . in alternative ask for refund of Rs 4 lakhs with 18%pa interest
2) if company fails to deliver plots or refund file complaint before consumer forum for deficiency of service and seek orders for delivery of plot . in alternative seek refund of Rs 4 lakhs with interest
3) also file criminal complaint of cheating criminal breach of trust against company and its directors