Please, clarify what do you mean with "sent to me the same way as the others", the Serial Number surely works, the things you can do wrong are:
- You inserted the correct Serial, but for another product. To activate JFK, you need to select JFK first, before clicking the "Register Serial" button
- You typed the Serial wrong. It has to be IDENTICAL to the purchase receipt. Respect lower/upper case (it's usually all upper case), don't forget the hyphens, and don't confuse the letter "0" with the number "O". Identical.
- You entered something else instead of the Serial Number. The Serial Number is not the Order Number or the SKU. It's the Serial Number and it's labeled "Serial Number" on your purchase receipt.