My license dissapeared after Windows 10 upgrade

I purchased a license key for Norton Internet Security for using on laptop, everything were fine until Windows say I need upgrade my computer from Windows 8.1 to Windows 10.

After the upgrade, I was unable to find my license key any where, even check back this Norton Account on web which I used for log in Norton software previously.

Please tell me why? How can I get back my license back for money? The stupid software now saying my trial was expired!

I'm very very disappointed with Norton the way they design software working like this.