What did they do? Did PayPal remove over $1000 from your balance? How is it even legally possible that they can take money or freeze accounts willy-nilly?
Usually it works this way. Buyer purchases your item, then files a chargeback against the credit card company. The money you got from that buyer is then taken out of your PayPal account.
Oh yeah, I have heard of that. It is a big problem for merchants selling digital goods, especially those without DRM. The buyer can do a chargeback after copying the data.
It is even worse when stolen credit cards are involved. For example, the game publisher TinyBuild claims that people bought their games in their webshop with stolen credit cards who then performed chargebacks and resold the keys on the grey market G2A. Then the story gets a bit fuzzy. I think TinyBuild could revoke the keys, but the end-users bought them in good faith on G2A, so that could backfire.
https://www.kotaku.com.au/2016/06/g2a-fires-back-at-developer-gives-them-three-days-to-provide-suspicious-keys/
I had also a first hand experience with that. Sold some digital goods from a game, buyer pays with a stolen credit card. Money got chargebacked. Case closed and nothing I could do about it. Lost only around $100 but it still bothers me. Since then I started to sell for BTC and got involved in the cryptoworld and here I am