You have to use the Refund action on Shopify to reflect the restock of items correctly in Sumtracker.
Case 1: Refund is done for an unfulfilled order on Shopify
When refund is issued on Shopify for an unfulfilled order, Sumtracker detects if the items have to be restocked based on the Restock checkbox on Shopify.
If you select the restock items checkbox, the products are put back in stock in Sumtracker. There is no adjustment to inventory needed as the product was never shipped for the unfulfilled order. The inventory is released from Booked stock and added to the Available inventory.
If you do not select the restock items checkbox, the inventory products is reduced in Sumtracker. There is an inventory adjustment created in Sumtracker to remove the product from inventory, since the product was not shipped yet.
Please check this video showcasing both the methods and the inventory adjustment that gets created when restock items checkbox is not selected.
Case 2: Refund is done for a fulfilled order on Shopify
Please use the Refund action on Shopify to reflect the restock of items correctly in Sumtracker. If you use the Return action, the restock of items is not detected by Sumtracker
When refund is done through the Refund action on Shopify, Sumtracker detects if the items have to be restocked based on the Restock checkbox on Shopify.
If you select the restock items checkbox, the products are put back in stock in Sumtracker. There is an inventory adjustment created in Sumtracker to add back the product to inventory, since the product was already shipped for the fulfilled order.
If you do not select the restock items checkbox, there is no change in the inventory in Sumtracker as the inventory was already reduced for this item when you fulfilled the order.
Please check this video showcasing both the methods