Redeem Google play credit?

A colleague wanted to get vbucks for fortnite and accidentally added the credit to his google play account, but had to redeem the code in fortnite. What should he do now?

You have to be able to pay with it even if it is downloaded via Play

Does not work

As I understand it, he wanted to treat himself to Fortnite VBucks and redeemed the Google Play credit on his mobile phone. Is he playing on the phone?

No, but he still had a google play map over

No plan why

Is too complicated for me