E-bay / Chargebacks / Condition Issues

anasarcasm

I recently had a buyer leave me negative feedback in regards to an LP's condition. He failed to contact me before he left the feedback, effectively ruining my 100%. For the record he claimed it was a G at least and I played/rated it before I sent it. It was a vg+. Anyway, I didn't notice the feedback for about a week and a half, at which time I posted a response and negative feedback about him not understanding record grading systems. It was a tame enough message. He retaliated with a nasty e-mail and initiated a Pay Pal charge back. It was a fairly cheap record and I just refunded him in full, but am very annoyed that I had to eat the priority shipping, delivery confirmation, and price of the record. I didn't want my account frozen as I was in the midst of many listings.I know that the general rule of thumb is that almost all disputes end up in favor of the buyer. My question is what are the situations in which they will side with the seller? What do you need to protect yourself? This is slightly different because it's about condition vs. not getting the item period. How would Pay Pal be able to prove record condition either way?