how to retrieve deleted emails.

When you delete emails, they go into the Trash folder and stay there for 14 days.  After that they drop into the "Recover Deleted Items" folder and should be in there for another 30 days.  If its only been 2 days since you deleted them, they should all still be in the Trash folder.  How are you accessing the email?  Are you using only the webmail interface, or a client like Thunderbird or Outlook?  Did you try running a date range search for any of them?

@uggiesam How many emails were you able to recover? Are you using the Xfinity email website or a third party application to access your emails?