[mothered]

Think yourself, just pick something that has similar weight.

Any stock Item that's significantly cheaper and weighs roughly the same.

As long as Amazon stock It (Inventory), they cannot declined your claim.

So, I should I order the "wrong" item and claim that's what I received? Aren't they gonna ask for me to send it back?

If I'm correct , you order the item you want. Then go to a different shop (so it doesn't show up in order history) and purchase the item that weighs similar. Then send the things that weighs similar back to Amazon claiming that's what they sent you.

Exactly this ^

They must stock It In their Inventory. Simply put, as far as you're concerned, they've shipped the Incorrect Item. Given they stock It, unless a stocktake Is done (which It obviously won't for one measly Item), they cannot prove It wasn't sent.