ReadyNAS RN214 Accidently Volume Data EXPORT I want to IMPORT Same NAS

Unfortunately, you cannot import a primary volume.  I have been unable to determine how a volume is marked/changed to "exported", so don't know how to directly reverse that.  Is the volume the only one you have and a RAID that has at least one drive of redundancy?

Manually mounting via SSH might work just to recover your files, but I've not tried that.

If you have multiple volumes, then exporting the primary will switch another to primary and all you need to do to re-import the exported one is cycle power.  Note that the imported volume will not revert to primary, that you'll have to restore all file permissions, and anything in user shares will have to be moved via SSH because they are not visible in any other way.

If you have a 4-drive volume that's RAID5, which I suspect you do, then you can recover your data in this manner:

Remove all drives and install a scratch drive containing nothing you care about and create a new volume on that drive.  Since your old volume was named data (the XRAID default), then the new one will need another name.  To do that, turn XRAID off, destroy the volume, and create a new one.  When you initialize the new volume, don't create the default shares.  Or if you did, delete them.  You can't have new and imported shares with the same name.

Now, turn off XRAID (if still on), shut the NAS down, insert 3 of the 4 old drives (if your new drive is in bay 1, use the drives from bays 2-4), and power up.  The NAS will import the old volume as a secondary volume, but it will be degraded because one drive is absent.  It will re-sync the OS and swap partitions, so that will take a few minutes.

Next, back up your files, as the next steps can be troublesome.  If there are files in personal shares, they will have to be moved to a normal share via SSH before you can copy them with a backup job.

Then, DESTROY the new one-drive volume and the NAS will change your imported one to the primary.  It will not, AFAIK, restore user shares or apps.

Lastly, with power on, remove the scratch drive and replace with the 4th from the original volume.  That will have to re-sync.

If you have only one "layer" to your volume (you have not expanded with larger drives since it's creation), you should then be able to turn XRAID back on.  If you can't, you'll have to destroy and re-create the volume to get back to XRAID 

Make sure you keep that backup current.  If something did go wrong in turning your re-imported volume back to primary, you'll have to destroy and re-create it then restore files.  And you may not immediately recognize that there was a problem.  Or, if you have the time and want to avoid any potential issues, just choose to destroy and re-create or to factory default now.

Note that I have only used this procedure on "sandbox" NAS's, and did so twice (A RAID1 on a 2-bay and RAID5 on 4-bay), but I did not use either NAS for an extended time following this procedure.  The issues I had with destroying a primary volume actually occurred in a different experiment, but I suspect could occur here.

Of course, if you already have a good backup, the simplest thing is just to start over.  But if that were the case, you likely wouldn't have come here and asked how to re-import.