Tsp8 There is an in-game setting under the first settings page called "communication filter". You can change this setting from "everyone" to "friends only" or to "no one", which will block incoming voice and text chat from non-friends, (or everyone), however do keep in mind that your voice and text chat will still go through, (and if you manually unmute anyone, you would have to manually remute them if you wish for them to be automatically muted again).
While this setting has been awesome for me, it may not be a solution for you if you like to still talk to randoms on your team.