Hmm, there are two options when you checkout on paypal, one is to pay direct from your paypal account into another - in that case the person has no idea about your private data - but there is also the option of paying into paypal using credit card details. This must mean the site owner then gets a record of your credit card details, there is no other way the person running that site could have started using my bank account for withdrawl
Whatsmore I got a confirmation email back i remember from the guy's website with my bank details and account number with the last few digits crossed which suggests paying with bank card into a paypal account lets the site owner see your bank information
If you pay via credit card to PayPal, the funds go from your CC to your PayPal Account and then to the recipient's PayPal account - they definitely do not get your CC details. I don't know how you were scammed out of your bank details, but it wasn't through PayPal