Hello and thank you for using Just Answer,The customer is correct. The US does not have VAT. In the US each state controls their own sales tax and only business entities have Sales Tax Numbers issued by the individual state or states that they do business in.It is my understanding (after reading the VAT requirements of Belgium) if you export goods to a customer (business or private) outside of the EU, then you do not need to charge VAT. You must quote the reference Exempt from Belgian VAT – article 39, §1 of the Belgian VAT Code on your invoice, and you should make sure that you keep in all cases proof of dispatch/delivery of the goods to support your exemption.
If you sell goods to a customer who is not registered for VAT in another EU Member State, you will have to charge Belgian VAT.
When the recipient has no Belgian VAT identification number and/or in the framework of intra-Community transactions, the foreign VAT number under which the customer is identified for VAT purposes and under which the supply of the goods or services is performed to him/her.