Hi @rafamem,
Thank you for sharing the information. We are extremely sorry for the inconvenience caused.
It seems like the custom gateway plugin is using the default WC order_id instead of our sequential order number. If you like to make the custom gateway plugin compatible with our Sequential Order Numbers for WooCommerce, please make the below tweak.
Instead of referencing $order->get_id()
when fetching order data, use $order->get_order_number()
. Try this out and let us know how it goes.