We can't know anything without proper system information and other details. Start by checking your online account whether or not your plan is actualyl already active and then download the CC app.
Does your Cloud subscription show on your account page?
https://www.adobe.com/account.html for subscriptions on your Adobe page
If yes, Log out of your Cloud account... Restart your computer... Log in to your paid Cloud account
http://helpx.adobe.com/creative-cloud/help/install-apps.html to install or uninstall
Cloud Getting Started https://helpx.adobe.com/creative-cloud.html
If no, This is an open forum, not Adobe support... you need Adobe staff support to help
Adobe contact information - http://helpx.adobe.com/contact.html
-Select your product and what you need help with
-Click on the blue box "Still need help? Contact us"
-or by telephone http://helpx.adobe.com/x-productkb/global/phone-support-orders.html
Sorry I cannot help, I have had SO many problems with Adobe software and none of the supposed "fixes" work. I am greatly disappointed with Adobe and their substandard products and abysmal customer service.
I'm beside myself, I cannot even find the words to express the frustration and rage I'm feeling right now --my work is due and I cannot accomplish it because, surprise surprise: Illustrator CC is once again, (much like
Adobe's non-existent customer service): "not responding!"