Sars trying to make a recovery through customs services

I recently bought stuff from abroad online it's ridiculous how they charge foreign manifest more than 50% of what the value is and every time their values keep going up and we never get communication on why we paying so much more than what we used to cause how we suppose to do business and compete if we are over taxed for shipping from abroad and there is inconsistency in charges for the same value in just about a few months