I'm sorry to hear of this. It is unfortunate that evil still exists. And we call ourselves civilized.
I don't know about European logistics, but I would recommend:
(1) Use your credit card when paying via PayPal. This is the only protection you have if things go bad. Unfortunately, I have had to use it twice, in over 100 transactions.
(2) PayPal and eBay protection is random. Often they side with the seller. They have improved, but I don't use eBay now, so cannot speak about the current status.
(3) Even on RFF, send money with your credit card via PayPal. You won't get burned.
(4) Repeat: CREDIT CARD via PayPal. Only send cash to people you know. It doesn't matter if the person has many postings on RFF, some of these people have scammed on this site. There is a lot of history here.