Potential SQL Injection Vulnerability

My web server firewall was blocking access to the plugin's ability to filter records on both this plugin and the PayPal Button Manager that Nishit is building. There are more details at the bottom of this issue: https://github.com/angelleye/paypal-wp-button-manager/issues/37

Nishit was able to make an adjustment to get this resolved, and we need to make the same adjustment here.