Like most of their products, your purchase gives you access to their support forums. This is considered your "paid support" even though pretty much every other developer offers user forums for free. And there is little developer involvement in the forums, so you won't receive much help.
Basing your site on a CCK is a big decision that will affect everything else you do. If you are an advanced Joomla user, then Zoo can be a great way to go. If you are a beginning or intermediate user, stay clear of Zoo. It will make your life very difficult.