add_filter( 'wcfmmp_store_address_string', function( $store_address, $vendor_data ) {
    return WC()->countries->get_formatted_address([
        'address_1'  => $vendor_data['address']['street_1'],
        'address_2'  => $vendor_data['address']['street_2'],
        'city'       => $vendor_data['address']['city'],
        'state'      => $vendor_data['address']['state'],
        'postcode'   => $vendor_data['address']['zip'],
        'country'    => $vendor_data['address']['country'],
    ], ', ');
}, 10, 2 );