Whats wrong with your calling option

Do you have VoLTE enabled on your device?  VoLTE is required to make and receive calls.  What device are you using?  Prepaid or Postoaid?  Are you connected to the T-Mobile USA network?  If not.  Have you tried manually searching for networks and then selecting T-Mobile?  Have you tried powering off your device for a minimum of 5 minutes to allow the sevice to drop off of the network to refresh the connectiin to the T-Mobile network?  

Call system not working i also used land line and it's the same.

When calling T-mobile customer care it says use 611 or the phone number then hangs up.