Centos7 might have XFS as root partition instead of ext4, so debugfs won't work. Note that recovery chances are pretty slim if you haven't unmounted filesystem as soon as possible or made a dd(1) image of it to other place.
Your best bet would be to try TestDisk and PhotoRec (recovers more than just photos, though):
Or you could go the manual route if you remember part of file contents by grepping the disk image (would only work for text file you remember), like so:
Note in any case you'll waste a lot of time, and usually might be able to recover only parts of data or damaged data. If it is more than few files, the effort required might be very uneconomical.