For Contour1, there is no undo for deleted recordings. Your recovery options are to watch available episodes of the series on either your DVR's OnDemand or on https://watchtv.cox.com with the Browse>TV option.
If the files were originally under Recordings, scroll to the bottom and recall from the Delete...for Contour2...If your DVR is the original older version, I think you are out of luck, and must find under OnDemand, like CurtB says.
If Contour2 has a deleted recorded programs undo, it may be the first Contour2 feature that I like better than Contour1. But, it's still a feature that's only useful if you answer "Yes, Delete" to the Delete Series Programs verification... or whatever the equivalent delete verification is for Contour2.
CurtB...just checked my Contour2.....if you 'delete now' a show that appears under Recording, you can scroll to the bottom and scroll thru the 'Recently Deleted' and either do a Recover or Delete Now. There is no Delete All for all the entries, you must do one complete delete at a time...same with recover. Kinda neat. Probably there is a link for Contour2 delete.
Now if you want to delete an entire series from future recording, I believe you must go in Series Priority and delete the entry.