Advance received against sale of land.

based on your agreement terms you can revoke. else as per contract act to refund.

Section 51: Monies Forfeited Characterized with Income from Other Sources

In case the advance money received in course of negotiation for transfer of capital asset but the negotiations does not results in the transfer of such capital asset, accordingly the amount is forfeited, then as per amendment by finance act 2014 it would be chargeable to tax as income from other sources under section 56(2) (ix) in the income of receiver of advance money