Implication of returning earnest money by legal notice

On 16 Dec 2019, we signed plain paper agreement to sell property. Agreement text included:- a) last date for execution of agreement - 30 Jan 2020. b) conveyance deed from PUDA should be issued to us by 10th Jan 2020 (since we didnt have conveyance deed). c) earnest money provided was 2Lac cash, and two cheques of 10 lac each dated 30 Dec 2019. d) in case buyer backs out, earnest money to be forfeited and in case seller backs out he should pay double the earnest money. We applied for conveyance deed on 5 Jan and even after giving heavy bribe, conveyance deed issued by PUDA only on 18 March 2020. After that lockdown happened so finally conveyance deed could be registered in tehsil only on 12 May 2020. We submitted the 2 cheques in our account only on 6 March 2020 before cheque validity was going to end. Only one cheque of 10 L was realized, while other 10 Lac cheque was bounced. In between there was no communication from buyer, but on 18 May buyer verbally refused to proceed with the deal. Instead accused us that we were not supposed to deposit cheque, and it should only be deposited after conveyance deed issued. Now buyer is harassing by not signing the cancellation agreement and even demanding the 2L back in cash. If I return the 12 Lac money into buyer account through NEFT and send him legal notice now that agreement stands cancelled, what will be the implication? a) Can buyer still go to court and demand that interest should be paid to him from Feb till June? Also can he claim any damages or double of the earnest money? b) If we try to sell the property to next party, then are we free of risk that previous party can again harass and try to take stay in court ?