1:: Have a Steam wallet code amount you want in mind.
2:: Go to http://g2a.com/ OR http://kinguin.com/ and purchase the game normally.
3:: You will receive a key. Log into your main steam account with a VPN (VPN not required but does cover your tracks more) and redeem the code.
4:: Log into a secondary steam account without the VPN (Again not required) and try to redeem the key. You will get a error.
4b:: Alternatively just try redeeming the code again and screenshot the error.
5:: Screenshot the error.
6:: Navigate to the G2A support hub or Kinguin support and go to the live chat.
7:: When the chat starts, send them a screenshot of the error and ask them for a refund.
------>8 - G2A:: You will get a refund and you can purchase games or withdraw it to your PayPal account after a few days. You can also ask for a replacement, which will also take a few days. Take it as a 200% ROI investment!!
------>8 - Kinguin:: You will be sent a ticket asking for more info. Fake it and send it back to them. You should get a refund/replacement asap.
9:: Important! Don't abuse this too much! Make it look legit.