Avira Antivirus Security for Android provides the ability to block a specific contact or incoming phone number. Before you add the selected contact to the "Blacklist", you can also decide which function should be blocked.
Calls & SMS
Blocking a contact
Start the app.
Select the function Blacklist.
Tap Add contact.
Open the list where the required contact is saved.
Add the contact to the “Blacklist”.
Select the option you want to be blocked and tap Save.
Any upcoming contact by a Blacklisted number will be displayed in your notification bar.
Further details of any Blacklisted number can be viewed in "BLOCKED EVENTS".