In order to redeem your product follow the instructions:

Enter here: https://www.wtfast.com
Log in or register a new account if you don't have one yet (Remember that you have to verify your email after registration and payment details such as a credit card or PayPal) 
After you've logged in to your account, enter here: https://www.wtfast.com/member/Subscription/UseCode
Enter your code in the provided field and click "Activate".

(You can cancel your subscription after the key activation. When you cancel your subscription any, and all scheduled future charges associated with the subscription will be canceled. However, your account will remain active for the subscription period you are paid through)