Seller agreed refund (but I can't post back a digital license)??

[howonearth]

I explained that the license was digital but PayPal have cancelled a dispute because I didn't "post back" the purchase. 

I received an email telling me the seller agreed to the refund, but PayPal have not refunded me so I'm really in the dark about how I can take this further.

Any advice? 

Where do I go from here?

Any help much appreciated.