Alright, so the mexican equivalent of gamestop is giving away codes to download the shiny gengar and the only thing that you need to do is to create an account and then go onto this link
>https://gameplanet.com/pokemon-sg/
You can create your gameplanet account here and then just link your email on the first link
>https://gameplanet.com/customer/account/create/

pic related, hope it helps some anons around here