Restore Submissions from before downgrade

Good day! I would like to know whether it's possible to retrieve submissions for one of our forms. We downgraded last April 8, and we were surprised to see that our 1700 submissions for one form were suddenly deleted. We had no chance to back up our data. 

That data is particularly crucial to our school system. We feel as though the mechanics for downgrading and what happens to our data after downgrading were not properly explained.

Free accounts can only store up to 500 submissions.  Any submissions in excess of 500 will be hidden with the oldest submissions being hidden first.  The data is not deleted.  I restored the submissions but since your account is significantly over the storage limit, those submission will be hidden once again in the next day or so.  I would recommend backing up the data before then.