If there's an open dispute in PayPal then a refund has not been sent yet. PayPal places a hold on the funds during a dispute. That sends a status back to JVZoo that looks like a refund and also removes your access to the product until the dispute has been settled. If the dispute results in a refund product access will not be restored and if the money is not refunded you will once again have access to your product.
The only way to complete the refund process at this point is to either complete the dispute, or close the dispute. This is something that you will need to work out with the seller directly or through the dispute process within PayPal's resolution center.
It is important to never close a dispute if you are not certain that the seller will return your funds, as the dispute cannot be reopened in PayPal once closed.