To ensure that your 2CO account is out of Demo Mode, you need to completely remove any instance of demo=Y, demo= or input type=hidden name=demo value=Y. When using the Demo feature for testing purposes, please be certain to clear the cookies in your browser between tests to ensure the new account settings have been applied. For more information on clearing the cookies please click here.
The demo mode is also controlled by an account level setting inside of your 2Checkout account. Log into your account and access the Site Management page and be sure you have not selected for all sales to be demo sales with the Account Demo Setting option.
If you are still having problems, please submit a tech support ticket and a representative will be glad to assist you.