I recieved a code from my work GameStop last year in where I had to use GOG app to install Witcher 3 and now after coming back to play it on a new machine it is removed from my account? Whats the Deal #gog

Posting on the forum won't solve the issue. If the game really is missing, you need to open a support ticket.
Try logging in to GOG through a browser to see if you can see the game there.
Are you sure you're using the right account ?
Check old e-mails for a message from GOG with confirmation that the game was added to your account and make sure it's the same e-mail address you're using to log in now. Subject should be 'Your order #xxxxxxx is complete!'.