Shocking customs duty charged

I ordered a book as a Christmas gift to the value of R289 from overseas and was charged the sky high shocking amount of R840 in customs duty when I fetched the book at the Post Office. I asked the Post Office if there was anything I could do about it. The Post Office told me that its no use trying to get in contact with SARS or asking for a re-assessment. They are still awaiting cases that were taken up with SARS in 2015! I tried to call Customs in Cape Town but they dont even answer the telephone. I find it hard to believe that SARS is now charging such ridiculous import duties. I feel that I have been ******.