I switched to Verizon about a year ago and have had repeated problems with my voicemail failing to work.  I will set it up and it will indicate it is working and then without notice I get an email or phone call from someone that tells me that they had previously attempted to leave a voicemail but get a message that my voicemail has not been set up.  This has happened 3 or four times to me with my LG Android phone and my brother has had this problem several times on his I-phone on his account.  I am in need of a transplant and have been waiting to get an appointment at University Hospital for 2 months.  I just found out today that I missed an appointment on January 7, 2015 and that several attempts to leave messages were made without apparent success.  The RN in the transplant clinic thought I had received one of the messages but I haven't heard a thing.  This is obviously a big deal as I was in the hospital 3 times late last year and need to get this going.  What do I do to stop this problem from happening?  The problem originally started when my phone was telling me to use a trial for visual voicemail which I declined each time but yet had my normal voicemail account disappear,  Help me please.