There is one solution to this problem, which is the one I used before I gave up selling on eBay for good.
What I used to do would be to set the estimated delivery date on the selling template so that the expected date of arrival would be slightly further into the future than it would probably take for the item to turn up. The reason I did this was to allow for delays in transit, as that way, so long as the item arrived by the estimated delivery date that I'd set in the listing, the buyer would end up thinking that the item had arrived on time, even if it had ended up being delayed in transit by a few days.
With regards to buying postage labels from eBay I always used to steer clear of this option as I don't trust eBay to effectively manage this type of thing, and as such I always used to purchase postage labels directly from the Post Office, making sure that I despatched the items as quickly as possible after the buyer had made payment. Using this combination of extending the estimated delivery time on the listing and also cutting out the middle man - ie: eBay - when buying postage labels and purchasing them direct from the Post Office always worked for me, even in instances when I had to post the items to overseas buyers. As soon as I got back after posting the item to the buyer I would log onto eBay, add the tracking number against the relevant item purchased and it would then update to show the buyer that his/her item had been despatched.
Although it might seem like a break from the norm if you are used to buying postage labels directly via eBay, it may well be worth trying out what I have just explained above to see whether or not it results in any noticeable improvements. If you were to purchase your postage that way then eBay would not tell the buyer that the item had been despatched until you had added in the tracking number manually.
