Board Thread:Questions and Answers/@comment-36055837-20180702103702/@comment-33362357-20180806003731

First bind your account. Make sure you have your account key and password.

Umm... don't sideload FGO first of all. Create a U.S. Google Play account, add it to your phone in Settings, switch to it in the Play Store, clear cache and data for it in Settings and you should get the U.S. store. Once you have the U.S. Play Store loaded, search for FGO and download it.

You may have to use a U.S. VPN to access the U.S. Play Store. In that case, switch to your U.S. Google Play account in the Play Store and then start your VPN (I recommend ProtonVPN). You can turn off the VPN after searching for FGO. Once FGO pops up, you can download it. No need to bother with the VPN after this. The game will update normally without you having to do a thing.

After that add your account on the title screen. Then go to Da Vinci's Shop and open up the SQ page. You can now add your PayPal to Google Play and buy SQ that way. If you don't have a PayPal, just make one and use it for FGO only.