How often do you sell on eBay. IME, eBay will side with the seller more often if you have made them (ebay) money in the past. I had issues with people trying to screw me when my feedback rating was low. Now that I have over 600 feedbacks, eBay virtually sides with me no matter what.
I am curious though, what are you doing when you document what you have shipped? Are you videotaping yourself package and ship the item? It may sound ridiculous, but I have done that on some higher value items, mostly for the peace of mind (have never had to use it). The real issue is you, as the seller, can ship virtually anything to the buyer and the buyer can ship virtually anything back to you.