Did you buy Illustrator thru Adobe? If so, you need to sign into your Adobe ID and download AI. If you can't, then contact customer service and they should be able to help you. I find their twitter account is oftern the way to go @AdobeCare
Sorry to hear about your experience. Please make sure you are signed in using the correct email. If you are, please try signing out and signing back in. You may also check the subscription details on https://accounts.adobe.com
I am also moving this discussion to "Get Started" community for expert help.