First, check your Google Play settings to make sure your card is current and correct, also check if any parental controls are active, that might limit your purchase abilities. If you use Gift Cards and are in the US, check if the balance cover the tax too. Do you have a 2 Factor Authentication (2FA) enabled? If yes, did you verify the purchase using the 2FA method enabled?
The sceren capture tells you to contact support, this is a player to player forum.
In-game: Green .... > info > online support > square talkbubble top right in the popup