We made a sale of computer software to a company in Italy. They paid 5% less than our invoice because of the "tax agreement between Italy and the US to avoid the double tax charge". They are telling us that retaining 5% is the amount of taxes that our company will have to pay in the US. I cannot find anything about this "agreement" and they have never done this before. They are sighting Article n. 12 - which is very hard to decipher.
Can someone help me with this?