Display pledged amount per Campaign

Hello everybody,
I would like to display the amount a user has pledged for a campaign. Ideally, I would like to implement it into a widget where it would show for each logged-in user how much they pledged per campaign.

I have found a total spent widget for woocommerce that looks like this:

add_shortcode('user_total_spent', 'get_user_total_spent');

function get_user_total_spent( $atts ) {
    extract( shortcode_atts( array(
        'user_id' => get_current_user_id(),
    ), $atts, 'user_total_spent' ) );

    if( $user_id > 0 ) {
        $customer = new WC_Customer( $user_id ); // Get WC_Customer Object

        $total_spent = $customer->get_total_spent(); // Get total spent amount

        return wc_price( $total_spent ); // return formatted total spent amount
    }
}

// USAGE: [user_total_spent] or [user_total_spent user_id="118"]

I couldn’t figure out how to change it to the total spent per product id.
Could anyone give me a hand or recommend an easier way?
Thank you in advance,
Best Regards,
Denia