How to tell if anybody has blocked your phone number on their Iphone?

How can you tell? I've been trying to get ahold of my friend but it goes straight to VM says like* you have reached VM service of (number)* and I tried call him from my friend's number to make sure if my number is blocked but it goes straight to VM… He has iphone6 plus and carrier is sprint.

Ask the person you're contacting.

You won't have any other way: a blocked number won't alert the call recipient but will treat the call as if the phone is turned off or otherwise unavailable and redirect your call. But non-blocked numbers will also get that if the phone is turned off or unavailable to take calls.

Call from another phone and ask them