that's how G2A gets games? I didn't know that.

Not all of them, presumably, but anyone can sell keys on G2A, and it's a haven for criminals. One very easy way to "launder" money from stolen credit cards is to use them to buy game keys, and then sell them to other people who are (presumably) not using stolen credit card information.

ok well thanks for helping me figure this out/ info on G2a.

No problem. You are not alone.

Basically g2a is just a "marketplace". So some thief with a stolen credit card buys game codes with it, resells them on g2a to turn it into cash. Eventually the credit card owner finds the fraudulent charges and gets them charged back. Sometimes the process can take months.

Looks like you need to contact g2a and see about getting your money back. And the same can (and does) happen with stolen credit cards and Steam games too.