I want to block some numbers for some reason but I did not get how to block I saw other answer you gave but there is no option called 'block number' in my windows phone Nokia Lumia 520 now what to do?
If you are on WP 8.1 (Denim update), you can set it easily. Head to settings > call + SMS filter >and turn it ON
Next, tap on phone dialer > long tap on the number you want to block > and tap block number .
For you to be able to block a number, it has to be in your call log. You cannot block a number from the contacts(people) list.
So, the easiest workaround: First dial the number you want to block, for less than a second, so that it appears in the call log (don't let it ring, please..lol). Then once it's in the call log, long tap on it, and the block option should be there. If it's not there, you need to activate the feature by going under Setting, then looking for Call + SMS Filter