i have Komplete kontrol s61mk3 and brought the upgrade for komplete ultimate and when i try to register the serial it says base product missing and now my kontakt 8 becomes demo and not useable
It sounds like you've bought an upgrade from a product you don't have, which is easy to do! The best idea will be to put in a support request as they can check your account to see what you have and what you need. You can do that here - https://bit.ly/n1acc
If you bought the wrong upgrade in the N.I. shop and that the upgrade does not work with your account then you can ask for a refund : N.I. Purchase Support
In case that you need guidance contacting support : Please read : how to get support !
Also, when logged in , then you can always see price for relevant upgrade offers for registered products on the My Komplete Offers page
So yep, as I said you need to contact support.