I sold an item for just over �300.
The buyer purchased it, I sent him an email thanking him and letting him know I was going to send it.
The next day, I sent it by Special Delivery (thus, have proof of sending, proof of delivery with signature).
The next day, the item is successfully delivered to the buyer.
The day after, I get an email from PayPal saying that the buyer has marked the payment as fraudulent (someone using his account); they launch an investigation to it.
4 days later and I've still not heard anything about it. I ask PayPal, and they tell me that they decided that the fraud was genuine, so have taken the money out of my account and given it back to the buyer.
How this is fair, I don't know. How they decided that the fraud was genuine (in a few days, with no police use to check the place it was sent to), I also don't know.
Now, the address was not PayPal-verified, so I was not covered under their seller protection policy (actually, since about 2 months after I sent the item, this has changed in their terms and conditions and now it is ok).
So even though I read through their help pages and did everything I was supposed to do, and was assured that it's normal (of course it is, PayPal can't verify every address), and that their fraud team are great, I've lost �300.