****** by international post via ******* SARS import duty

I ordered a book from the UK. Books are not subjected to import duty as per the SARS website. However I was charged R150. I queried the charge and was told to call SARS. I called SARS and they said SA Post sets the charge, they just collect. I went back to the post office and was given an email address for International parcels. I emailed them three times over 6 weeks and also emailed customer service twice. I did not get a reply. I have been ******.