Certain messages I receive seem to disappear after a time spent in my inbox or even after I transfer them to a folder. Is there something I can do to prevent this from happening? Or is this a glitch in the system?
Verizon's email retention policy states that email in the inbox will remain for 120 days. If you move those emails into your personal folders, they will remain indefinitely until you have used all of your storage capacity. You will then have to clean your send folder, trash folder and remove any old email that may not be needed any longer.
If webmail is losing emails, odds are there's a client somewhere pulling email from the server. This could be on a pc, phone, or other device. Even if you have no idea where the offending client is, you should be able to resolve it by simply changing your webmail password to something different. This will stop the client from authenticating, and it won't be able to remove your mail anymore.