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Terms of Use

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These Terms of Use ("Terms") govern your use of Unknown Call Blocker ("the App"), developed and maintained by Alpha System. By installing or using the App, you agree to these Terms.

1. Acceptance of Terms

By downloading, installing, or using Unknown Call Blocker, you acknowledge that you have read, understood, and agree to be bound by these Terms. If you do not agree, do not use the App.

2. Description of Service

Unknown Call Blocker is a free Android application that blocks incoming calls and dismisses SMS notifications from phone numbers not saved in the user's contacts. The App uses Android's CallScreeningService and NotificationListenerService APIs to perform its core functions. The App also offers an optional Community Protection feature that can anonymously report blocked unknown numbers and sync confirmed spam numbers.

3. User Requirements

  • You must have an Android device running Android 7.0 (API level 24) or higher.
  • You must grant the necessary permissions for the App to function (see Privacy Policy for details).
  • You must set Unknown Call Blocker as the default call screening app when prompted.

4. User Responsibilities

You are responsible for:

  • Managing the permissions granted to the App on your device.
  • Understanding that the App will block calls and SMS from numbers not in your contacts.
  • Maintaining an updated contacts list to avoid blocking desired calls.
  • Reviewing the blocked calls log periodically to check for false positives.
  • Using Community Protection responsibly if enabled, including not attempting to abuse, overload, or interfere with the reporting service.

5. Disclaimer of Warranties

The App is provided "as is" and "as available" without warranties of any kind, either express or implied, including but not limited to implied warranties of merchantability, fitness for a particular purpose, or non-infringement.

Alpha System does not warrant that the App will be error-free, uninterrupted, or that it will block all unwanted calls or messages.

6. Limitation of Liability

To the maximum extent permitted by applicable law, Alpha System shall not be liable for any indirect, incidental, special, consequential, or punitive damages, including but not limited to:

  • Missed calls from legitimate sources (e.g., banks, hospitals, delivery services)
  • Blocked two-factor authentication (2FA) codes sent via SMS
  • Loss of business opportunities due to blocked communications
  • False positives or delayed updates in optional community-confirmed spam lists
  • Any damages arising from the use or inability to use the App

7. Intellectual Property

All intellectual property rights in and to the App, including but not limited to the source code, design, graphics, and documentation, are owned by Alpha System. You may not copy, modify, distribute, sell, or lease any part of the App without explicit written permission.

8. Modifications to Terms

Alpha System reserves the right to modify these Terms at any time. Changes will be reflected in the "Effective Date" at the top of this page. Continued use of the App after modifications constitutes acceptance of the new Terms.

9. Termination

You may stop using the App at any time by uninstalling it from your device. Alpha System reserves the right to discontinue the App at any time without prior notice.

10. Governing Law

These Terms shall be governed by and construed in accordance with the laws of the Federative Republic of Brazil. Any disputes arising from or related to these Terms shall be resolved exclusively in the courts of Porto Alegre, Rio Grande do Sul, Brazil.

11. Contact Us

If you have questions or concerns about these Terms, contact us at: