Well you can't expect them to risk their business over this. I see their point about it being close enough that it might go over the threshold. I also see yours that it apparently did not go over. But if I were in their shoes I might risk loosing a customer to be sure I survive an audit.
Could you cancel and buy less at a few places?
As I said before, I requested cancellation as soon as I purchased it in November 2013, because I realized I wouldn't be able to receive it (I had a flight to catch, never expected to take half a month to get a "next day" delivery).
They refused it.
Now, they are still refusing cancellation and refunds.
So now I am here without gold and without bitcoins.