ACFW – Fraud prevention on one-time coupons

  add_action( 'woocommerce_checkout_process', function() {

      $coupon_code   = 'your_coupon_code';

      $billing_phone = wc_clean( wp_unslash( $_POST['billing_phone'] ?? '' ) );

      $billing_addr1 = strtolower( wc_clean( wp_unslash( $_POST['billing_address_1'] ?? '' ) ) );

      if ( ! WC()->cart ) {

          return;

      }

      $applied = array_map( 'wc_format_coupon_code', WC()->cart->get_applied_coupons() );

      if ( ! in_array( wc_format_coupon_code( $coupon_code ), $applied, true ) ) {

          return;

      }

      global $wpdb;

      $order_ids = $wpdb->get_col( $wpdb->prepare(

          "SELECT order_id FROM {$wpdb->prefix}woocommerce_order_items

           WHERE order_item_type = 'coupon'

           AND order_item_name = %s",

          wc_format_coupon_code( $coupon_code )

      ) );

      if ( empty( $order_ids ) ) {

          return;

      }

      foreach ( $order_ids as $order_id ) {

          $order = wc_get_order( absint( $order_id ) );

          if ( ! $order ) {

              continue;

          }

          $phone_match = ! empty( $billing_phone ) && $order->get_billing_phone() === $billing_phone;

          $addr1_match = ! empty( $billing_addr1 ) && strtolower( $order->get_billing_address_1() ) === $billing_addr1;

          if ( $phone_match || $addr1_match ) {

              wc_add_notice(

                  __( 'This coupon has already been used. It is only available to new customers.', 'woocommerce' ),

                  'error'

              );

              return;

          }

      }

  } );