I have tried so many solutions for this but I can't figure it out. Here is a simplified version of the plugin code:

```
class YITH_Vendors_Frontend_Premium extends YITH_Vendors_Frontend {
    public function __construct() {

    add_action( 'woocommerce_register_form', array( $this, 'register_form' ) );
}

```

So I want to remove this action from my child themes function.php.

The problem is the class is not instanced via a variable. Instead it is instanced like this:

```
class YITH_Vendors_Premium extends YITH_Vendors {
public function __construct() {
public function init() {
            $this->frontend = new YITH_Vendors_Frontend_Premium();
    }
  }
}

```

This class however is never being instanced via variable. Instead there is a function that instances it:

```
function YITH_Vendors() {

    if ( defined( 'YITH_WPV_PREMIUM' ) ) {
        return YITH_Vendors_Premium::instance();
    }

    return YITH_Vendors::instance();
  }

```

And then it's just called like that:

```
YITH_Vendors();

```

I tried all these but no chance:

```
remove_action( 'woocommerce_register_form', array( "YITH_Vendors_Frontend", 'register_form' ), 999 );
remove_action( 'woocommerce_register_form', array( "YITH_Vendors_Frontend_Premium", 'register_form' ), 999 );
remove_action( 'woocommerce_register_form', array( "YITH_Vendors", 'register_form' ), 999 );
remove_action( 'woocommerce_register_form', array( "YITH_Vendors_Premium", 'register_form' ), 999 );

```

Please help! Thanks!