Its stupid really,  a simple function would be to have a "holiday mode", ebay has it.  Where all listing are simply "not visable" to buyers for the period your away.   Editing my 450 lisitngs individually is not something I have time for, if you deactivate and let them time out in the days before, thats a good deal of lost sales and starting it all up again is a pain, redoing stock levels etc.

A little patience required on the buyers part by the looks. These things happen.  

Providing the seller gives a 100% refund,  I see no reason why they cannot back out of a sale. I have done this, for the same reason as Callum,  however in my case the buyer got very abusive, threatening me with the police etc. My mistake was also very obvious, a $950 item offered for $9.50

We have actually removed many items from trade me, purely because we were paying listing fees and unable to find the items in search results and were getting no views at all. Unlike other platforms where even if spelling is a little off, you still manage to find things.  Trade me just gives the, "We couldn't find anything matching your search. Have another go – you could try a broader search, or double check the keywords you entered"