All I can say is that either your device is not contacting google play or google play is telling CC that your installation is not licensed. There is no workaround for this.
If you have set the google account credentials correctly, then another possibility is that your device is not being allowed to talk to google's license servers. This can happen if there is a firewall on your device, for example DroidWall, or if your wireless connection does not permit internet access.
If you have checked all of this and still cannot make it work, then we will refund your money. In CC, touch the menu button (the three dots), select Help, then Email. This will create an email message to my son Steven, who deals with google play. Give him your google play account id (email address), the approximate time of purchase, and if you can the google play transaction number. He will give you a refund.