Ebay own Paypal, you now pretty much need Paypal to buy and sell on Ebay.
Credit card fraud on the web is out of control. Paypal must get some false positives when they run checks.
I can totally understand your reluctance. Personally, I would have just handed my bank details to them. They might be a pita at times but they're superlegit and the UK arm is covered by Data Protection so your bank details are going nowhere.
Bummer tho what happened to you. Just don't use Western Union or MoneyBookers instead
