When you see the following error on an Android device, please note it is NOT our application. We do not handle the billing, Google does. What this means is that Automatic Fraud detection has blocked your account from making additional purchases.
This usually resolves in a day or so in time, and is simply becuase you either have a new account and are trying to purchase too much, so Google feels your credit card is stolen, or your credit card is being used by too many accounts on Google. Either way, Google is the only one who can resolve this.
You can contact Google through Google Play https://support.google.com/googleplay/?hl=en
This link is also useful: https://support.google.com/googleplay/answer/2851612?hl=en&ref_topic=6046241
This is what the image of error looks like: