Block failure happens for multiple reasons.
In order to specify the problem, please check your phone with the following instructions.
- Did you set up Whoscall as the "Default phone app"(Android7,8,9) or "Default caller ID & spam app"(Android10 and above)?
- Did the number still appear in the "Blocked History"?
- Did the number still appear in the "My Blocklist"?
Also, please notify us via the app. We will be happy to help you with the problem.