I have added a new payment method but it wont allow me to do in-game purchases

I used a vanilla visa gift card and an apple giftcard credit in order to add a new payment method because my previous visa giftcard expired. Although I have added a new payment method, this would not allow me to do in-game purchases. When I try do any purchases, it leads me to a pop up saying : “your purchase could not be completed (For assistance, contact iTunes support at www.apple.com/support/itunes/ww)”. How could i fix this?

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