Sorry to hear that you've now lost out twice.
Understand clearly that how (or even if) the seller sent it is their responsibility, and it is not your problem.
They entered a contract to deliver it to you. They have not done so, and it is unreasonable for them to delay refunding you this long.
If ParcelFarce have seized/destroyed/lost/stolen it, that's between them and the seller. Don't enter into any discussion with them about that.
So as above, raise a dispute with your payment provider, speak only to them, and cross your fingers. I really hope that you didn't just send it via PayPal without any sort of invoice.
For future reference, always get a clear, unambiguous contract for delivery from the seller. I ask sellers to produce a PayPal invoice listing the goods, delivery method and total cost: this also flushes out lazy twunts who just say "delivery and fees extra" - make
them work out the total that they want you to pay.
If the seller baulks at providing an invoice, shenanigans are likely afoot and you should look elsewhere.
https://www.paypal.com/uk/webapps/mpp/email-invoice
Best of luck.