Forms missing submissions

Many of our forms are missing submissions.  Previously we were able to download all submissions received for that form, now many show 0 submissions or are only showing submissions from this year.  Can previous submissions be restored?

Also, we received an email last night stating that we had received our submission limit, however, we still have close to 10,000 submissions available.  Why would we receive this notice?  I want to ensure continuous availability to our forms.

I have checked and currently you have 509  submissions stored on your account.

I also saw that your account was upgraded to Silver plan on March 24, 2017. For free accounts total submission storage is 500 submissions. Most likely before you upgraded your account your oldest submissions were removed because of this limit. 

I have restored your submissions. Now you have 7,571 submissions on your account. 

Hope this will help. Let us know if you need further assistance.