You can either block any number from your contacts list, calls, or add unwanted number manually.
Numbers from the blacklist are blocked. Whatever you do, you will not be distracted by phone calls.
Add numbers into black and white lists here. You can choose to block both or either of calls and SMS from Blacklist. The calls and SMS from numbers in Whitelist are defaulted unblocked, but you can modify as you want. The block rules can be modified in block mode.