Why I cannot pay with my google play accounts?

[AC Question]

I am from outside of Google play support country. I was hooked up in some game and i decided too buy in game currency with Google play account. So i bought Google play gift card. But I cannot as it was not support in my country so i used hola vpn and fake us phone number for recharged and it was success. The problem is i cannot buy with it. It says you need authentication for purchase and required password. I entered password correctly but it said error. I went and removed require authentication for purchases in google play store setting but it also need password and the same error.
Pls help me solve this