Elfie saved me a bunch of time and effort with a concise summary of Amazon.com's listings for the Only single. Rather than paraphrase, I'll copy, paste, and slightly edit what he said.
"To clarify about amazon cancelling orders for the Only
single. Unfortunately when the item listings were originally created, they didn't know exactly which versions of Only
were which, so they just listed a couple of them at first using the same item numbers across their different sites (US, UK, Germany, etc).
The item they had listed as "Part 1" on the US site was using the same ASIN (Amazon's item number system) as the DVD single on amazon.co.uk
. They can't sell that DVD on the US site because it's PAL and probably region-encoded. That's why the orders for "Part 1" on the US site were cancelled. The three track
and the four track CD
versions are still both available, and will both ship. And of course the DVD is available on amazon's UK site