I have a number of problems using 8.1.1. Shows extended, many calls must be called twice before going through and not ringing after phone is not used for awhile.

[radiotradio]

Our iphone 5S phones are 2 months old.  Using 8.1.1 software.  Shows extended LTE, doesn't ring after the phones are idle for awhile (not obvious setting) and we must dial twice quite often before the call goes through.  These phones (we have 2), so far have been pitiful performers.  What gives with apple or Verizon for not getting these problems repaired? Repeated calls to Verizon and going to the Verizon store has not helped.  Help!