First you should try to do a factory reset from the dashboard and see if that helps. Give it time to complete the process otherwise you could end up with this problem
http://community.wd.com/t5/WD-My-Cloud-EX2/EX2-Reset-now-can-t-get-it-back-working/m-p/839505/highlight/true#M2251
If that didn’t work then i would try the hard reset from the back button.
According to the info from WD thus process should not delete the data on the HDDs unless you format the disks.
PS: one NAS does not mean backup. It’s only storage. You need one more device to do a backup for this NAS. I strongly recommand that you also try to do a backup via USB and see if that works.
