Installing Webroot Security on my PC

I just purchased Total Tech Support membership with the Internet Security Software for my PC.  I was told that when I got home all I had to do is open the Webroot Icon on my computer and I would be instructed to add the Key Code to start the process.  When I opened my email from Best Buy, it had a prompt that said “Install Internet Security. I pressed that prompt and It took me to a screen where it asked me for my Key Code and also to sign up for the Internet Security Plan for $249.00 and wanted me to give my credit card info.  Note, I have already paid for the subscription at the store.  I am confused.  There was nothing on my computers WebRoot icon that asked me for the Key Code.  It only stated that my subscription was expired.  I am lost as to what to do next.  Please help!!!!