Just purchased upgrade to Enterprise. Sales rep sent me a "how to" on upgrading to Enterprise. The video shows the ability to upgrade to Enterprise when you click on the license level. When I click on the license level, it says contact sales. We've signed, claimed domain and ready to roll. Just need assistance with next steps.
Normally after it takes a few days after you sign and pay your contract for enterprise features to be activated. Your sales rep should have explained this to you. People on this board cannot help with individual account issues. I recommend you contact either your sales rep or support.