I needed two pairs of something and called up to put in an order. “I need two pairs of X.” I emphasized that more than once. I guess I’m going to have to find a phrase that’s more unambiguous and explicit than “two pairs,” because, at least to the guy I was talking to, “two pairs of X” is not meaningfully different from “two of X.” So I got only one pair.
It might help if we knew what these things are, but if you want to avoid ambiguity altogether, how about saying “I need four…”?
What were the objects that you were asking for pairs of? Perhaps the confusion may have occurred as result of them being objects that are not generally found in pairs, such as pears.
If I requested two pairs of pears from Paris, I would expect to receive anywhere from 1 to 8 objects.
Two pairs of glasses = two objects.
Two pairs of aces = four objects.
You’re going to have to be a little more specific, I think.
Two pairs of pants should get you four legs worth yeah?
If you told me you wanted 2 pair of scissors, you would get two cutting devices.
If you told me you wanted to 2 pair of jeans, you would get two pants.
If you told me you wanted 2 pair of headlights. You woud get four headlights.
Send me a pair of scissors. And oh hey, as long as you’re at it, send me another pair.
I think that’s my point. I didn’t think there was any ambiguity.
In none of these cases, would one expect that asking for “two pairs” would get you only one pair, as commonly understood, whether it’s pants or scissors or glasses or shoes or elephants.
In any case, they were ankle braces, which come in pairs, one for the left foot and one for the right. I asked for two pairs. When I went to pick them up, I saw that there was only one pair. I said this to the guy I ordered them from.
Me: “I asked for two pairs.”
Him: “There’s two in there.”
Me: “There’s two ankle braces. That’s one pair. I wanted two pairs. That’s four ankle braces.”
Him: “Oh.”
What you have there is a garden variety idiot, not a shift in the English language.
Ankle braces? I was thinking socks, so I was pretty close.
I wouldn’t order four socks when what I wanted was two pairs.
I don’t know about that. Now that I think about it, I have vague recollections of other situations in which “two pairs of X” and “two Xes” were used to mean the same thing.
And I’m not talking about pants and scissors. I’m talking about things that when singular aren’t considered pairs.
So, if you want “4 hammers”, why not say that instead, of “two pairs of hammers”?
What are you talking about? Are you following the conversation?
In any case, I can conceive of there being some kind of set of hammers that is sold in pairs, say, a regular claw hammer and … uh … another kind of hammer. In that case you might ask for two pairs. Why not?
I was thinking shoes but it also works out the same.
If I asked for two pairs of shoes (or socks or ankle braces), I’d expect four items.
I agree that the OP’s seller was an idiot.
But ankle braces IME don’t come in pairs. Lots of people only need one.
^This. If it normally comes as a single, ordering it as two pairs, when you want four, is just setting yourself up for confusion.
First of all, ankle braces, like shoes, are different for the left and right. It makes perfect sense to ask for them in pairs.
Furthermore, unless you don’t share the same understanding of the word “pair” that I do, I don’t see any “set up” for confusion at all. Even if you’re right and ankle braces are sold as singles, there’s no way that “two pairs” means anything less than four.
I agree as well. How hard is it to ask for four ankle braces? I’ve injured my ankles on many an occasion, but never both at the same time; I have doubts I’ve ever needed two ankle braces, let alone four. Did your giraffe have an accident? 
Ankle braces can be bought singularly. But they do come in an obvious pair - right and left. So two ankle braces are not necessarily the same as a pair of ankle braces.
His inability to understand two pairs doesn’t change the meaning. It just means he is an imbecile. Treat the guy as such.