@Muhammad_Anas — that’s not a Vietnam or India trick, that’s the tell of a carded/synthetic account mill. Walking through why:
├─ ChatGPT’s promo eligibility checks the billing address on the card, not the cardholder’s nationality or real location — same mechanism as the Mexico/Rappi mismatch above, just aimed at India/Vietnam’s cheaper ChatGPT Go tiers instead.
└─ A random seller holding live cards with matching Vietnamese and Indian billing addresses on demand isn’t running two personal bank accounts in two countries — that’s a BIN farm: stolen/leaked card data or synthetic identities picked to match whatever region’s promo is being farmed that week, then the “pre-activated” account gets resold before the real cardholder’s bank flags the charge.
What happens after you buy one: the moment the actual cardholder disputes the charge (days to a few months later), OpenAI reverses it → account banned, and the payment trail on file is now your delivery point, not the seller’s. You’re not skipping the region check, you’re holding stolen-goods risk.
Actual free/legit route — already above 
and confirmed by @GhostX’s link: Revolut Standard → 3-12mo ChatGPT Go bundled in-app, zero card gymnastics, nothing to get clawed back.
!