Hi there,
actually found the solution. In plugin folder src/main.php just add // (comment) before following line.
//Override the Item Price on product page
add_action('woocommerce_get_price_html', array($this->Wcd, 'overrideItemPrice'), 100, 2);
So it will look like this:
//Override the Item Price on product page
// add_action('woocommerce_get_price_html', array($this->Wcd, 'overrideItemPrice'), 100, 2);