I haven't had many disputes over the years, but i have had to run through the process about 3 times in the past couple of years.
I bought a used trail gator in the summer and it was described as being complete with all parts and in good condition. The condition was indeed good but it was incomplete, with the ball for the forks and the rear dropout stowage bracket missing, making it both useless and dangerous to use. I questioned the seller and they held firm it was complete and that it was never supplied with those parts, even saying that they must have been added later, complete horse poo. Anyway I went via a paypal dispute that time and after sending it back at sellers costs I was refunded, paypal just dealt with the money side. I bought a new one in the end as it was on discount and only about £10 more.
The other times were when I had items delivered from high volume Chinese sellers, I raised eBay dispute as items either failed or were not sent. After a week or so of radio silence from the sellers eBay just refunds you, if the item is faulty, just I binned them as there is no value in sending back such low value things. The sellers in this case probably just ignore the correspondence as they know eBay will just refund the buyer and it's not worth their time to deal with it, just let the system work.
The problems are when sellers from the first example start to drag things out. Pics help as do manuals and spec sheets from the web, in my case I had issue 1.0 of the manual showing the missing parts and how to fit them. Seller had no retort.
The postage receipt for customs will obviously be good evidence as will pics and a dispute raised not the same day. I am sure you will get everything back but post office charges.
I have often wondered about LGF's example and a few times when I have sold mobile phones have pictures the serials and IMEI number stickers in case I get a dishonest buyer. This has happened to me in the past but always outside of claim limits and always with PC equipment, one such example was a laptop that went out working, after 3 months buyer upgraded harddisk and put on a new OS and complained it didn't work! Was told exactly where to go then...
Carl.