Thanks Niloy, we’ll consider to use the premium version for the site.
And thanks for your tip Dave, I commented this lines:
// Unhook and remove WooCommerce default emails.
// add_action( 'woocommerce_email', [$this, 'unhook_woocommerce_original_emails'] );
// New order notification only for "Pending" Order status
// add_action( 'woocommerce_order_status_pre-ordered', [$this, 'newPreOderNotification'] );
// add_action( 'woocommerce_thankyou', [$this, 'sendOrderEmail'], 9999, 1 );
// $email_customer_invoice = WC()->mailer()->get_emails()['WC_Email_Customer_Invoice'];
And as far as I tested is working perfect ??
Stopped sending the duplicate receipt, and now the client is receiving the rest of emails (Processing, Complete Order, Notes to Customer). Not Cancelled is not sending though (admin notification).