Urgent: stamp duty & enforcement of agreement

Buyer in Karnataka, Seller in Rajasthan, Property in Punjab.

The agreement to sell is made on Rs.500 Karnataka stamp paper, executed in Punjab and at 0.1% of deal value will need more stamp duty to be paid. The agreement has to be ENFORCED.

Can the extra stamp duty be paid? Has it to be paid within the period the agreement is valid for? Or, is it okay if it is paid later?

The second question is: Where can it be enforced? In Karnataka, Rajasthan or in Punjab?

Thanks