I think you need to breathe for a minute here...
No one advised on you that...because that wasn't the issue you were posting about. You wanted to know about paying...not about protection, or anything else.
To be honest, if we tackled every potential hurdle with that you may or may not face in a transaction...we'd never get to do anything else with our lives. There are potentially hundreds upon hundreds of ways a sale can go bad...when it does it's unfortunate.
The responsibility of authenticating an item and buying/not buying is yours. I would contact eBay and PP...hopefully you can get somewhere with them. However, I caution you to use a friendly tone...you get more bees with honey than you do with vinegar.