Hello,
I am really sorry to know you are experiencing problems.
You seem to be using an old version of the plugin. That might be the cause of the problem. Please update the Cost of Goods plugin to the latest version, 2.7.3, and the WooCommerce plugin to 7.0.1.
You can download the latest version of the Cost of Goods plugin from here.
Kind regards,
Moshtafizur