Android - Blocking phone numbers
Block calls from specific numbers added to your block list.
Launch the Phone app and tap 
→ Settings → Block numbers.
Tap Recents or Contacts, select contacts or phone numbers, and then tap Done.
To manually enter a number, tap Add phone number, enter a phone number, and then tap 
.
When blocked numbers try to contact you, you will not receive notifications. The calls will be logged in the call log.