Topdser has the feature to void order that you do not need to fulfill on Topdser.
Go to "All Shopify Orders" list and find the order you to void, click" Void Order". Please note void order will not change the order status on Shopify.
How to restore order
Go to Voided Order list, find "Restore Order" Button and click it.
The order will go back to "Awaiting order" status again.