How can I block specific phone numbers (i.e. unknown numbers, international phone numbers...)? Whoscall Service Center September 10, 2020 07:09 If you want to block specific phone numbers, please take the following steps: Tap “Block” on the upper left side tab. Choose the block rule you want to block. Related articles Why do I still receive calls from the blocked numbers? I activated the "Caller Identification" function, but why are there still some numbers unknown? Why is my number of the information displayed in Whoscall? Why do I have to set up Whoscall as the "Default phone app"(Android 8,9) or "Default caller ID & spam app"(and above Android10)? Why do I still get voicemails from numbers I blocked? Comments 0 comments Article is closed for comments.