Sir,
if you have not transferred possession of the property and the ownership is still vests with you and more importantly if the total consideration is unpaid, then you can cancel the present deal.
However it need to be bear in mind that, If the Sale Agreement was registered wherein the period mentioned for the payment of balance consideration is still remains, then in that case, other party should claim for part performance.
I advise you to kindly engage a advocate for further proceeding
Regards
Kishor hajare/hajare.kishor@rediffmail.com/9930647734