How to purchase item in game

The game is very fun. But why can't I purchase items in the game? And the currency of the purchase doesn't match the currency of the country I live in.

Game is good but can someone help me regarding payment issues that I am facing. The game tells me that that "The product 8s bot available in your country" while I attempt to pay for the premium. What kind of error is this and what to do regarding this issue.