Chartboost closed account for invalid reason

After a few years working with Chartboost today I’ve received the following email:

We noticed abnormal activity and/or details on your account or associated account that violate the Chartboost Terms and Conditions here.
Our data suggest that the users of your published apps may not be real users, and that earnings may have been generated fraudulently.
Your login, publishing, and advertising capabilities have been turned off and you will not be receiving payment of the earnings balance. You may direct any questions or follow up information to us at [email protected].
The Chartboost Team

This is a total invention since the app is distributed normally on the Google Play Store. If this sources does not provide real users then I do not know what does.

I have tried to get back to them but I’ve received an email stating that

[b]we have confirmed fraudulent activity… Your account will remain permanently suspended. This decision is final and any further communication will not be reviewed. If you would like more context on this decision, please refer to the Chartboost Terms & Conditions. We are dedicated to maintaining the health of our network on behalf of all of our clients and we appreciate your understanding.

Please refrain from further correspondence with any other Chartboost team member regarding this decision.

Chartboost Publisher Review[/b]

Anyone else experienced this?