You can only redeem Gift Cards that are denominated in the same currency as the country where your Roblox account is registered.

Roblox is a free-2-play Massively Multiplayer Online (MMO) game developed and released by Roblox Company. During the game, players can create their unique avatar, and explore virtual worlds created by other players. Thanks to Roblox Studio, players can easily create their own content like mini-games, items, and even whole unique worlds, and share them with the rest of the community. Players can even sell their creations earning Robux, a virtual in-game currency.

Roblox Gift Card is the easiest way to top up credits for your (or your friends') Roblox account. After using the digital PIN code you will instantly add a certain amount of credits to your account, that can be later spend however you want. For example, you can buy VIP Server access, avatar additions, mini-games, etc. Besides many advantages, like instant delivery, Roblox Gift Cards are 100% safe. The process will not require you to share your credit card number or any personal information that could be used against you.