If your order is not automatically set to completed in Shopify it could possibly be because you have requested fulfillment of the order. Once you click this button in Shopify you deprive the GOGETTERS app of the ability to process this order. Also, we can no longer add shipping once the button is clicked.
Fortunately, the order will ship as normal, after all, it was successfully sent to the supplier.
If you have not clicked on fulfillment requests yourself, there may be a setting in Shopify that is wrong. In the images below you can see which setting is involved, the setting should be as shown in the screenshot.
We are unfortunately unable to set the order to completed if request fulfilment has been clicked. Therefore, it is important that you do not click this button on orders that have gone through the GOGETTERS app.