Husband & I just upgraded. My mega works fine. His s4 however is irking me. No way to use it unless he's at home with wifi! Music Zone even state's, "not available with this carrier" when you try to open it. Hello! Its sprint! No sprint zone app either, instead it's "mobile zone," which also will not open. We are ready to just ditch sprint altogether. Nearest store is 80 miles away.
Samsung made an app to fix this. Go to the play store and download the "refresh customization" app. Complete option 1 and then 2, this will cycle you phone on and off a number of times and restore the Sprint Zone app, missing roaming settings, and Sprint Spark to your phone. When this is done, go into the Sprint Zone app and view your device and check the dashboard, make sure you are current on all software updates, and install them if necessary. See if this works for correcting connectivity issues. If not enter ##72786# on your dial pad and let it cycle off and on once more.. Hope this helps.
Have the exact same issue as the original post (except I never tried the music app), phone was also bought around the same time as original post. No data access unless connected to wifi.
Settings -> About Device -> Status -> Mobile Network Type: LTE: Mobile Network State: Disconnected
Tried response 1, from Sprint Care - No Change
Tried response 2, from digermania (I do have concerns over spelling errors in the app... makes me nervous about apps legitimacy if they can't spell customization correctly...) - AFTER option 1: Sprint Spark showed up, LTE is showing with a symbol I never saw before in the status bar at the top of the screen, - AFTER option 2: my custom app lists were replaced with samsung widgets (assuming that is how it came, I don't remember), Sprint Zone is back, I disconnected from WiFi and was able to connect, update profile, etc.
Mobile data now appears to be working.
Settings -> About Device -> Status -> Mobile Network Type: LTE: Mobile Network State: Connected