Third party app for call block

[Android Central Question]

Is the a 3rd party app for s8 plus that will block calls but not send it to voice mail, instead give an out of service message (or something bug similar)

 

[hallux]

That's a level of call blocking that has to be done at the carrier level. I believe many call blocking apps just reject calls, when any call makes it to your device and is rejected it rolls over to voicemail, there's no way for the voicemail system to know if the rejection was call blocking or a simple rejection by you. In order to get around that the call needs to be blocked before it gets to your phone.