Over the past 6 months I am having an issue of not receiving voicemails until late.  I have an iphone 7, update the iOs regularly.  Throughout my day I go from being on wifi to in areas with just cellular service multiple times.  When I do receive the voice mails it will be in a bunch all at once.  This morning someone left me a voice mail, I can listen to it if I call in and access my voice mail account but if I look at my voicemail through my iphone there is no indication of a message.  I just called myself and left a test voice mail.  Same thing If I call *86 my voicemail is there but I don't get any notification of a voicemail on the iphone and if I go to the call function and choose voicemail it does not indicate nay new voicemails.