Suppliers ought not accept an order from a retailer unless they are able to fulfil the order. This is not too much to ask, especially in this era of being always on, always connected.
It is frustrating placing an order to only have part of it arrive months later and not be able to tell a full story in-store.
Some suppliers are worse than others. The best way to deal with them is to complain once, louder the second time and cut them off the third time.
Suppliers need to have the systems and processes in place to stop this from happening, to stop taking orders when at the head office they know from forward orders or warehouse management that the orders cannot be filled. Anything less is not good enough.
I see this problems with big and small suppliers. It happens too often. Indeed, it peaks following major trade shows where some suppliers manually gather orders and take a week to key them in and see what their actual commitment is.
Once supplier told me they could not fulfil as my order and the order from a few others pushed them to another container and they did not want to risk it. What a way to run a business!
In the case of an out of stock where the supplier accepts unsullied goods as a backorder and has a need to send out a catch-up order, the supplier ought to carry the freight cost of this and not push the retailer to get to a minimum spend.