Zencart 1.56, PHP 7.2.

I have taken a mirror of my customers website and database. They need a 3rd party to come in and see why a plugin isn't working for a payment module. For security purposes, they would like all their customer data and orders deleted from the database.

I tried doing this in phpmyadmin, this only caused a problem when testing the checkout, the database encounted an error. Which defeats the purpose of them testing the checkout for their module.

Example:

DELETE FROM orders;
DELETE FROM order_history_status;

etc.

Is there another way to delete the data? I have seen many asking the same thing and they don't seem to have a solution.

Thank you for your time.