Usless service from KLM

We travelled from Amsterdam to Johannesburg on 11 July as a group of 4. All bags didn't make the flight. 3 of the 4 bags were delivered on 13 July, one mysteriously went missing, 10 days later has still not been found. We have been given the run around ever since, with each consultant telling us a different story on where our bag is. Our tracking number and file has also been abruptly closed. Infuriated is an understatement. If you ever need assistance, good service, or your luggage for that matter, don't even bother, the airline is a MESS!