If the person contacted you via a site message here on RenderHub, they definitely have a user account (would be a member of RenderHub).
And you can tell them YES. PayPal can be used for RenderHub purchases. It's right at the bottom of the checkout page.
If I am misunderstanding your concern, please let me know.
"patitas" is not on the vendor/member list of RenderHub.
As the entity 'patitas' is not a vendor/member - no valid (genuine) Paypal transaction came from this site.
Pay them nothing.
I suggest you report this to Paypal, and your bank (Advising bank will stop Paypal ignoring your advice it is a scam/false transaction).
From experience - Paypal are very good/very cooperative helping people against scams/scammers.
It appears to be a scam/fraud.