Yes, I buy from there a lot, there is also a feature called g2a shield to use when buying from people rather than the g2a company, this ensures your code works, if it don't then you get a refund or new code, although you have to use their "live chat" to use the shield service which means you have to wait in que, look for trusted settlers with tons of successful purchases before buying, I bought pixelpiracy, grid 2, gmod and a few others from there 😀.
shield = definite code, but long wait time, depending on the que
without shield, instant code through email but if it don't work then you're on your own.