Don't worry! You can still fill in this form and receive your winnings. Any forms you need to complete and a history of forms provided to you can be found by going to Menu > My Account > History > W2G, or by using the address below in your browser:
You will be able to complete any unfinished forms and review previously completed ones that are available for you to keep on your records. Once you have completed a form for a win, the win amount will immediately be credited to your balance for you.