You were clear with out mentioning you didn't use VPN with Stealths. I called it roulette because if it's working on some VPN it isn't guaranteed. It isn't worth buying virtual cards for use with a VPN if the seller's saying don't use VPN's because the card gets blocked.
I've never had a case where the card was blocked because a VPN was detected - the only thing that can happen to you is that you can't redeem the card with a VPN - but in that case, just turn it off and the problem is solved. Additionally, if you pay with a card that you redeemed with a VPN, then every transaction you make with it should be with a VPN, otherwise any attempt at privacy is completely unsuccessful.
Furthermore, most VPNs are just a fake appearance of hiding online anyway, if you do something bad they will find you without any problems.