Seller threatening to cancel Indeminity, Affidavit and GPA

Hi, We struck a deal with one of the property for X cr. We payed a token amount of 6 Lakhs and made an MOU mentioning that we will clear the rest of X-6 Lakhs in a months time. This was in first week of March '20. Then due to lock down, our funds could not be arranged as we had to travel inter-district to arrange for funds. So during the course of the period, the seller repeatedly was pressing on clearing the rest of the amount as per MOU despite knowing the fact of the situation of pademic lock down and pressing issues due to it. Due to persistent pressure from the seller, we further made payment of 6 lakhs more. But that didnt stop him from threatening to forfiet it if we dont clear it on time. Somehow with police permission, we travelled and arranged the funds. Now after we transferred complete funds to his account he then refused and troubled to come to registration office to complete the formalities giving reasons of health and covid issue. After pursuading and pleading he then decided to make it to registration office. Till this point, we got registration deed done, Indeminity, GPA and Affidavit and other essential documents which are required for cidco transfer. Also, we gave xerox of notarized copy of Indeminity, GPA and Affidavit and notarized the xerox copy as well and handed over to the seller. I am not sure why would seller require a notarized copy and why would buyer has to bear the notary cost that to on a xerox copy of notarized copy of Indeminity, GPA and Affidavit. We took signature from the seller that they have received that notarized xerox copies Now, as per the agreement, they were supposed to vacate the flat in about 20 days.They only had their stuff partially vacated and insisted us on getting NOC from police to transfer their luggage to some other place. To avoid any confrontations, my dad that too. But then, they caused trouble and delayed the possession by further two and a half days to which we kept quite to avoid any arguments. Now that seller is again asking for notarized copy of Indeminity, Affidavit and GPA and says we havent given it to him whereas we have written signature of him confirming he has received. And now he threatens to cancel Indeminity, Affidavit and GPA