I made an agreement for 1 month for sale of my land with an advance for 5000, in a stamp paper. If I take some more money after the agreement made form the buyer by writing on back side of the same agreement, is that a valid agreement. If he fail to pay the whole money in a month then what happened? Is that valid or void.
You may receive additional amount as and when paid by the buyer. The consequences of failure to pay will depend upon the terms of agreement.