Ups are in the wrong, under EEC regulations brought in any software even downloadedor anything else bought from a country outside the EEC, the company should charge VAT-Tax of the country ordered from.
It is up to customs when any packages from abroard come into the country if they want to open the package, and they can then charge import duty, and the post office charge for repackage.
UPS are stealing tax from the country they deliver to, certain goods imported into uk are EXEMPT from import duty.