Query regarding resale flat: sale agreement and sale deed

I did the sale agreement for resale flat in Feb/20 , I transferred token money, down payment around 13L and closed there ongoing loan of 20Lakh in feb/20 only. For sale deed only 7 lakh was pending to be paid. After that due to covid situation sale deed got delayed and old owner stayed in that house for next 8 months for free nor even paid property tax. Now when I am asking to pay only the relaxation old owner got on interest after me paying for his loan amount and due to which old owner was able to close loan account. And i was paying loan interest on that cheque amount due to which his loan got closed. So, I am asking only for the interest I paid on 20L in that tenure to the bank , not even asking for extra 13L i paid from savings . Old owner is denying to pay... I spent 33L and old owner had only 7L pending, they occupied the flat on that basis and used it.... now old owner is not willing to pay anything for that 8months tenure... what is the legal views on this ?