Delivery and payment finality differ

Steam says a redeemed gift is removed when its purchase is refunded because of fraud or a payment dispute. Its FAQ says the recipient's account is not restricted simply by that revocation, but the game is no longer available from that gift.

The upstream payment may be the problem

Steam's scam guide describes digital gift cards bought with fraudulent cards or later charged back. Our inference for cheap top-up shopping: a seller can deliver something before the underlying payment problem surfaces. This mechanism does not prove every discounted seller uses stolen cards.

Check the refund route before paying

Steam does not support third-party sales of Steam gifts and directs buyers to the seller for a refund. Our checklist: identify the seller and authorized sales channel, keep receipts, and never hand over passwords or verification codes for a promised discount.