This may not help you now, but in the future, I would suggest getting everything in writing. You can do a Buy/Sell Agreement, which states who the seller is, who the buyer is, what the agreed price is and when the transaction will take place. It should be signed by both parties and dated. That way, you have a CONTRACT. If you are in the States or on a US military base, you should also have it Notarized. Rule #1 - CYA!