Hi,
If the properties of the folder shows the moved folder inside that top folder, but its not visible in normal mode, then you can it in two ways
Is that a pst file? Remove and reconnect the pst.
Is that a ost file,? check whether you are able to see that folder in OWA. or reconfigure the outlook profile.
Locate the ost-file for your mail profile and rename it to .old when Outlook is closed. Upon starting Outlook, the cache will be rebuilt again; check the folder showing now.
You can also try to remov and re-add the email account and check if it helps.