Voicemail

Hi, so I have an iPhone 11 and it has come to my attention that I have not been receiving any voicemails. My visual voicemail is completely empty and when I call my voicemail it says I have no voicemail. I know that I should have at least three messages. So far, I have tried resetting the network settings, deleting all save voicemail in case it was full, and changing my voicemail password but nothing has helped. A friend suggested that I do a factory reset but I’m not sure if that will fix it. Any suggestions?