Sorry to hear you’re having troubles with your download.
At first you should to check your Envato Dashboard Statements page. Your Statements page should reflect all of your transactions.
If your statement page showing that the payment has done for the item then the item should appear at your download page. In that case you should open a Envato customer support Help ticket (if you haven’t done already) and let them know. Envato Customer support team will be happy to check it for you.