Customer bought more quanity than available.

How was a customer from a country we don't ship to buy 10 units of an item we only have 1 of. I cannot figure this out since I have shipping set for only USA and the item said it had only 1qty.

aunrea:

How was a customer from a country we don't ship to buy 10 units of an item we only have 1 of. I cannot figure this out since I have shipping set for only USA and the item said it had only 1qty.

Check in the Admin, there are a couple places that control the way inventory is handled. Check Admin->Confirguration->...
As for shipping, take a look at your settings in the specific modules and make sure everything is correct, overlooking one little thing can cause bigger issues.

In Admin>Configuration>Stock the 1st 2 items should be true and the 3rd should be false. The 3rd one is the one that stops a person from purchasing more than the available stock.

As stated, the Ship Zones determine the ability to accept/decline orders from specific countries.