WoW! Great advice, It's nice to see a
ecommerce hosting company admit that sellers are being ripped by buyers. I have in the past sent 2 and 3 of the same items to buyers who then report they never got them. I have had people download my entire site and I have proof via server logs and they then go get their money back from paypal. Of course it doesn't matter that I can prove they got their stuff. For awhile I felt like I was the local library.
Its good to see that Auctiva is addressing the issue.
Its always good to have a fair return policy. However, it doesn't do a whole lot of good as far as protection goes as far as pay pal is concerned. The buyer can technically keep the item and get their money back; essentially stealing.
My advise is to use a merchant account at least that way you have a little more protection against buyers who are just scamming. Also if the transaction doesn't feel right then cancel it. It will probably save you money and aggregation in the long run.
I knew there was a reason I liked Auctiva. Great job! Now when you get the automatic download part of your ecommerce site up and running, I will be looking into your site for a new home. Until then... I wait.
Take care and happy holidays!