MR LEE SIGNED A CONTRACT OF SALE TO PURCHASE LAND.IN ZAMBIA THE SELLER PAYS PROPERTY TRANSFER TAX. After making the initial payment Mr. Lee did not pay the balance payment because the seller underpaid property transfer tax. Mr. Lee wants to protect himself from any future risks that may arise due to the aforementioned situation. He has requested his lawyers to prepare a document that will reduce the risk to zero. 

As Mr. Lee's lawyers what kind of document would you prepare and what would you include.