Customers being erased, help!

I have a zen cart 1.3.8 that is losing customers for no reason. Every couple months the customer database gets wiped out. It doesn't seem to be any other zen cart table other than the zc_customers.

The other related customer tables are still there, so I have names but no way of contacting them. Plus that leads me to believe that they weren't deleted from the admin panel.

Any ideas on how to isolate this problem would be much appreciated, or has anyone even heard of this problem?

Also, I tried to REVOKE DELETE but then the cart can't erase sessions which breaks it.

Resurrecting this old message because the same thing has happened to my client!

She was getting an error in the admin about the customers table being missing, and when I check the database, the "customers" table is completely gone.

We haven't done any upgrades or coding changes to the site since February, and she has just been processing orders like normal.

It is an old version of the cart: 1.3.0.2

Add-ons: Orders Export, Export Email Addresses

I will recommend an upgrade, but would love more info on how this could have happened. Thanks!

Make sure the site has not been hacked and talk to the host, perhaps they made an oops with the database.

(definitely get it upgraded)