Seller not go for registery

I am purchase a property in delhi Rs. 25lac consideration . This property are mortgage of chola mandalam Bank from the seller side. I know and I m interested for purchase because I m takeover of this loan through bank as a Seller Bt terms. 1. So, we have to 1.50lac pay to seller on 29.11.2018 under agreement to sell and balance amount Rs. 23.50lac pay in three mode a) Rs. 412000 pay by buyer B) Rs. 16,77,000 amount transfer from buyer bank to seller bank c) Rs. 261000 amount dd make by buyer bank in favour of seller. And I take 3month time for pay this amounts. My Tim lapse after 28th Feb. 2. After all bank procedure my loan is sanctioned and make a cheque in favor of Cholamandalam Bank and rest amount cheque in favour of seller before agreement time. 3. But as per bank procedure buyer bank give loan cheque to seller and seller bank if, Seller do firstly registery and same day close seller loan. 4. All condition are fulfill and seller agree for registery. 5. 27th Feb seller and buyer go to registrar office, and buyer pay Rs. 412000/- to seller with written, same day stamp duty purchase and all paper complete with both banker verify this paper. 6. Both buyer and seller signed property paper with thumb impression in front of legal person. 7. But before submission of this paper in registrar office give a instruction, some official reason registery all stop by registrar office. 8. After registery open, seller are refuse and not convinced for go to registery for final prodecedure. 9. So, I am humbly requesting you to please help me for this issue.