Prevent call from going to voicemail after after blocking it on Android Phone

Question

We are programmaticaly blocking the incoming calls on an Android phone. We are successfully able to block the calls. However, the call goes to voicemail as soon as it is blocked. How to I prevent the blocked call from going to voicemail?

Answer 1

The only way I can think of is actually answering the call and disconnecting it immediately therefore "fooling" the mobile network and avoiding the voice mail

Answer 2

How to I prevent the blocked call from going to voicemail ?

Step #1: Raise a lot of money.

Step #2: Buy a mobile carrier

Step #3: Order the engineers of the mobile carrier to allow app developers to block calls going to voicemail

Step #4: Repeat steps #1 through #3 for each mobile carrier operating on Earth

In other words, voicemail behavior is up to the mobile carrier, not to you.