Wifi Calling on iPhone with T-Mobile?

So I have an iPhone 5 on T-Mobile and am wondering if there is a way to use T-Mobiles complementary Wifi Calling with my device. If not, are there any apps or anything that will allow me to call, except using my phone number? I really don't want to download a third-party app and then have friends save two numbers for my phone, 1 for calling and 1 for texting. That just seems kind of stupid. Thanks.

You can use your current phone number with Google Voice, which has an app called Talkatone on the App Store.

Have you tried Viber? Http://www.appfavour.com/social-networking/viber-free-phone-calls-text_382617920/ This app lets you communicate with other Viber users for free, and it separate your contacts from Viber contacts.