Two agreements for sale - registered and unregistered

Agreement for sale made and registered for Rs 25 lakhs with advance of Rs 2 lakhs on 31.7.15 in tamilnadu and also made another agreement on 31.7.15 for Rs one crores which was not registered and advance paid Rs 35 lakhs and recorded in the unregistered agreement also. For registered agreement the buyer has to pay the balance amount of Rs 23 lakhs and get the sale deed registered before 6 months i.e 30.1.2016. In the case of unregistered agreement the buyer has to pay balance amount of Rs 98 lakhs and get the sale deed registered before 30.1.16. All terms and conditions in both agreement are same except for difference in sale consideration. Buyer paid Rs 10 lakhs in Aug'15. Buyer has sent a notice on 10.2.16 saying that he has been approaching us for giving Rs 23 lakhs and for registration but we have not responded. But truth is we have been asking the buyer to pay Rs 88 lakhs and get the sale deed regd. What is the status of our case. What should we reply thru our lawyer. The intention is Rs one crore sale value.