Add a special commission for a specific gateway

wc_vendors_custom_commission.php

<?php

add_filter('wcv_commission_rate', 'm_commission_update', 20, 5);

/**
 * @param $commission
 * @param $product_id
 * @param $product_price
 * @param $order
 * @param $qty
 *
 * @return float
 */
function m_commission_update($commission, $product_id, $product_price, $order, $qty) {

    $card_gateways = array('stripe');

	$author = WCV_Vendors::get_vendor_from_product( $product_id );

	if ( WCV_Vendors::is_vendor( $author ) ) {
	    
		// check if the order was placed using the card!
		if ( in_array($order->payment_method, $card_gateways) ) {

		    // the commission you want to add - switch to whatever logic fits
			$card_commission_rate = 2;
			// add the card commission
			$card_commission = $product_price * ( intval( $card_commission_rate ) / 100 );
			$card_commission = round( $card_commission, 2 );

			// remove the commission from the payment that goes to the vendor
			$commission -= $card_commission;

		}

	}

	return $commission;

}