1.Insufficiency of stamp paper does not make the agreement invalid and hence on the basis of agreement even if executed on deficient stamp papers can be relied upon.
2. In this case since no advance payment was made the agreement was not acted upon at all
3.Now the seller can cancel the agreement and proceed to sell the proeprty to another buyer. There is no legal impediment in this.
4.on the basis of this agreement the suit can be filed but in that event the court may impound the agreement and ask the party relying upon the agreement to pay the penalty and deposit it in court.