Tap phone number you want to block

Tap “Details“

Tap Menu icon on the top right.

Tap “Block number“

You won’t receive any calls or messages from this number from now on. If you are OK with it,
Tap “BLOCK“

The number has been blocked. To unblock, go back to “Phone” and Tap Menu icon on the top right.

Tap “Settings“

Tap “Block numbers“

Tap “” to UNBLOCK the number

Well done!
You can also manually enter the number or add number from your contacts to block.