Disgusting customer service

Disgusting customer service! I sent an A4 envelope containing two pieces of paper in it from the UK to South Africa. DHL logged it into their system as weighing 9.9 kg!!! It already cost £35 to despatch, but because of this, they then wanted the recipient to pay a further +-R350 in “customs/import” fees. Can you actually believe it? No one bothered to go and find the parcel and confirm that it was indeed just an envelope! They even had a click button which said “write directly to the management”, which I did. Never had the decency of a reply!!! Unacceptable and pathetic arrogance!