I have a sim-free iphone 8 plus and i cant get ATT visual voicemail through the native phone app. its usually supposed to self-provision. i called ATT, they reset the voicemail, i went through the setup again, they said provisioning looks ok. I called Apple and they said that sim-free iphones still fully support carrier visual voicemail. I'm kind of stuck. Don't really want to spend half the day going to the city to replace it. Any ideas?