Just add the number to your silent list as described in our app help for iPhone following the steps below:
Tap the add to silent + sign icon.
Fill in the form: phone number, country, name or company name of the caller if you know it (optional), your comments and tap the Add button.
Report the number you just banned to the community complaints (recommended) and let others know. Once a number is added to the community complaints it will be banned on all phones using the Reverd app. If you choose not to report the number to the community, it will still be saved to your silent list.