solving issue with woocommerce bookings and retainful

wc_bookings_find_booked_day_blocks.php

<?php
/**
 * Retainful
 */
add_action( 'wc_ajax_wc_bookings_find_booked_day_blocks', 'rnoc_find_booked_day_blocks',9);
function rnoc_find_booked_day_blocks()
{
    $product_id = absint($_GET['product_id']);
    if (empty($product_id)) {
        wp_send_json_error('Missing product ID');
        exit;
    }
    try {
        $args = array();
        $product = get_wc_product_booking($product_id);
        $args['availability_rules'] = array();
        $args['availability_rules'][0] = $product->get_availability_rules();
        $args['min_date'] = isset($_GET['min_date']) ? strtotime($_GET['min_date']) : $product->get_min_date();
        $args['max_date'] = isset($_GET['max_date']) ? strtotime($_GET['max_date']) : $product->get_max_date();
        $min_date = (!isset($_GET['min_date'])) ? strtotime("+{$args['min_date']['value']} {$args['min_date']['unit']}", current_time('timestamp')) : $args['min_date'];
        $max_date = (!isset($_GET['max_date'])) ? strtotime("+{$args['max_date']['value']} {$args['max_date']['unit']}", current_time('timestamp')) : $args['max_date'];
        $timezone_offset = isset($_GET['timezone_offset']) ? $_GET['timezone_offset'] : 0;
        if ($product->has_resources()) {
            foreach ($product->get_resources() as $resource) {
                $args['availability_rules'][$resource->ID] = $product->get_availability_rules($resource->ID);
            }
        }
        $booked = WC_Bookings_Controller::find_booked_day_blocks($product_id, $min_date, $max_date, 'Y-n-j', $timezone_offset);
        $args['partially_booked_days'] = $booked['partially_booked_days'];
        $args['fully_booked_days'] = $booked['fully_booked_days'];
        $args['unavailable_days'] = $booked['unavailable_days'];
        $args['restricted_days'] = $product->has_restricted_days() ? $product->get_restricted_days() : false;
        $buffer_days = array();
        if (!in_array($product->get_duration_unit(), array('minute', 'hour'))) {
            $buffer_days = WC_Bookings_Controller::get_buffer_day_blocks_for_booked_days($product, $args['fully_booked_days']);
        }
        $args['buffer_days'] = $buffer_days;
        wp_send_json($args);
    } catch (Exception $e) {
        wp_die();
    }
}

add_action( 'wp_ajax_wc_bookings_get_end_time_html', 'rnoc_get_end_time_html',9);
add_action( 'wp_ajax_nopriv_wc_bookings_get_end_time_html', 'rnoc_get_end_time_html',9);
function rnoc_get_end_time_html() {
    $start_date_time  = wc_clean( $_POST['start_date_time'] );
    $product_id       = intval( $_POST['product_id'] );
    $blocks           = wc_clean( $_POST['blocks'] );
    $bookable_product = wc_get_product( $product_id );
    $booking_form     = new WC_Booking_Form( $bookable_product );
    $html             = $booking_form->get_end_time_html( $blocks, $start_date_time );

    echo $html; // phpcs:ignore WordPress.Security.EscapeOutput
    exit;
}