Seller wants to cancel the sale of land after getting earnest money

Hi, I ("seller") entered into a basic paper agreement for the sale of my plot worth ~ 20lacs (plain paper agreement) to fullfil the sale within 60 days. Buyer paid earnest money of 10,001/- Basis the oral agreement he had to pay the full money via cheque/DD. Later he insisted to take part in black and partly in white, he started to blackmail me, that he can sue me and keep the property on hold if I didn't agree. He also started to abuse me and wants me to sell the property forcefully. Later he has agreed to pay via cheque. As I didn't like the way he dealt, I want to terminate the deal with the seller due to his bad behavior. At any cost I don't want to sell to him. What are the rights of seller and to what extent the Buyer can have a claim on the property over and bove the ernst money paid. Should I send him a legal notice after the expiry of time period of 60 days? What are other remedies to safe guard my interest in the property. Look forward to your advise and suggestions. Thanks.