Scammer – Avoid at all costs.

I’m requesting a full refund from my previous seller, who turned out to be a scammer. The user in question has apparently scammed others on this platform before, as seen here:
https://www.epicnpc.com/threads/steamonly-alpha-boost-on-the-market.2981676/

This situation is extremely disappointing — I used EpicNPC specifically because it’s considered a trusted platform for high-value trades. It's unacceptable that a known scammer was still able to list and carry out trades here. I took all reasonable precautions and now expect the platform to take this seriously.

I would appreciate clear instructions on how to move forward with the refund process and any action being taken against the seller.