I assume you are referring to Linnworks desktop with this request.
We are in the process of rewriting Supply Chain management for Linnworks.net and will look to possibility of implementing this here.
There are no plans to add new functionality to the existing desktop purchase order functionality.
Unpaid Orders should not download until paid or at worst should be excluded from creating PO's using "Reorder Low Stock"
we are having nightmares with Amazon orders where customers never pay and then we have ordered the the product specifically. Its impossible to manually check UNPAID orders as we have 25000 sku's to deal with.
With Magento integrtaions this is not a problem, only seems to be other marketplaces such as Amazon and Ebay.
I would suggest this is a critical UPDATE!
I would like to request an option to exclude unpaid orders from appearing in the out of stock totals when creating orders using this option from open orders.