How to recover deleted files

My Cloud OS 3 Personal & Network Attached Storage My Cloud
3

Usual Windows delete, check the folder, click delete, ok the warning.
This happened twice but I stopped it real quick.
I had a good look around in the directory I was in, and lost two folders in that directory and about 20 files.
Other directories did not appear to have been affected.
I had backups, but not of this directory, it was one I had just created and moved files in to.