All of my 2020 emails have disappeared from my inbox

On Sunday, all of my 2020 emails disappeared.  I have spoken to both the comcast service and securuty service and no one can recover.  It states it will take 2 hours, but once completed they are still not  recovering 2020 emails.  It is not on my phone (IMAP) or if I log in wiht a laptop to comcast.  How can a years worth of thousands of emails just disappear?