The author implies he wanted an app to get his Voicemail like iOS. Nowhere does he say VoiceMail didn't work. The regular voicemail stuff just works on any stock Android GSM phone - you get a notification for new ones and you can tap that or long press 1 to go to carrier voice mail box for your old VMEs. I have that working on 5 different unlocked phones at the least on 3 different carriers. If you want an app - yeah you gotta find it in app store if your phone wasn't a carrier branded version - the app needs to do carrier specific things to get your voice messages and present you a list.

It worked - I have always used unlocked phones and you do get voicemail notifications without doing anything further. (There are still possibilities of issues if you bought European model it won't have US Carrier's APN Settings etc. but that's hardly reasonable to expect.) He wanted T-Mobile VoiceMail app to be bundled with it and also WiFi calling - both are carrier specific features which would have worked fine if he would have bought the right phone -T-Mobile HTC One. Expecting that to work on an unlocked, carrier unspecific phone designed to be LCD on as many GSM carriers is nothing but unreasonable.

> It took me forever to realize that I had to download the T-Mobile voicemail app to get my voicemail

That's all he says. Nowhere in the post he says voicemail didn't work - he implies he wanted an app to get his Voicemail like iOS. The regular voicemail stuff just works on any stock Android GSM phone - you get a notification for new ones and you can tap that or long press 1 to go to carrier voice mail box for your old VMEs.