Hi kathl1
If you are purchasing from the EU, our system internally checks your VAT ID through the EU's VIES system. So if your VAT is not registered there, there is no way to remove the VAT from our system (as this is a legal requirement).
I'd suggest you check your VAT on the VIES page and if it's validated correctly there but you still can't validate it on our website, please let us know and we'll check it out.
Best Regards,
Salva.