Netgear Nighthawk M5 (MR5200) Mobile Router never connects to fast.t-mobile.com

This is why I hate T-Mobile.  I went to three diferent store locations and none of them ever know what they are talking about. 

My Inseego mifi had issue and they were going to send me a replacement to one of the store locations near my house.  The support person said that it should arrive in less than 5 days.  It's been seven days and I called the store to see if my new replacement has arrived.  The store rep said she cannot tell me unless I go to the store and speak to them.  To me that is a waste of time if they don't have it.  I'm not sure what the big deal is.  Anyway, I went to to the store so that she can tell me my replacement wifi is has not arrived yet.  Haha!  T-MOBILE IS A JOKE!