Who I have the same questioned this topic

We've lived in the same house over 10 years and never really had any issues (zip code 28269).  Over the past few weeks my wife and I have noticed that people frequently can't hear us on phone.  It happens several times a day now.  When on the phone for a couple minutes everything seems fine and then all of a sudden they can't hear us and it eventually says call failed.  We thought maybe our phones were getting old, so my wife just bought a new Iphone X and she is still having the same problem.  I have a Galaxy S7 Edge and have the same problem.  So frustrating.  It has me considering switching or maybe even adding back my land line.  Anyone have any suggestions?

David