Emails older than year 2021 not found

I have tried using the Xfinity assistant and called customer service with literally no way to talk to a person because "email" apparently isn't something it understands. 

I have had this email account for decades, but for some reason I went to look back at an email from the past and it wasn't there. I sorted my email inbox and the oldest email that's on file is from 2021. I have emails on this account from 2005. 

I'm wondering why I cannot see my emails. I do not have any settings set to IMAP on the 1 device that has this email attached to it. Please advise as I'd like access to ALL of my emails.