Cancellation of property sale agreement

Hello Sir/s, If I have below clause in my original property sale agreement ; do I still need to do a 'Registered Cancellation Deed' in case the buyer is unable to pay the full and final amount in the stipulated amount of time? I ask because what if the buyer refuses to show up for the registration of the cancellation deed? I would like to be free of hassles of forcing the buyer to come forward for cancellation and thus I would want to be free to sell my property to other third party legally right from the date of my return of any advance money back to the buyer. Clause: The time is the essence of this sales agreement. The Transferees/Purchasers do hereby agree & undertake to pay to The Transferor/Seller the sum of Rs.xxxxxx) towards the balance amount of consideration by obtaining loan from any financial institution within 30 days from the date of registration of this agreement (subject to submission of all the documents by The Transferor/ Seller demanded by the financial institution of The Transferees/Purchasers) by way of RTGS/Demand Draft, thereafter The Transferees/ Purchasers have to pay 18% per annum interest on the said balance amount to The Transferor/ Seller for 30 days/ 1 month till the final rupee is paid. Thus after the 60th day from the date of registration of this agreement if the full and final payment is not received and realized by the seller from the the buyer; this agreement SHALL stand cancelled and null and void AUTOMATICALLY without needing any special cancellation deed or registration thereof. Thereafter the transferor/seller shall return the advance money if any realized earlier from the transferee/buyer; by way of NEFT/RTGS/Cheque/Demand Draft in favour of the purchaser. This return of money will be a simple capital sum and completely without any interest whatsoever. In case the purchaser refuses to accept the cheque or demand draft the money shall be transferred by RTGS/NEFT via net banking. Thereafter, notwithstanding any argument of defence from the Transferee/Buyer, the transferor/seller SHALL be at full liberty to sell the said flat/property to any other third party at any rate and terms as deemed suitable by the transferor/seller.