Bag lost enroute to Walvisbay

My bag went missing on the flight from ORT to Walvis Bay. According to the SA Express Walvisbay office my bag was offloaded by mistake on Sunday 10 September at ORT. It was instead of the bag of a passenger that did not pitch up for the flight. I arrived 14:30 and at that time it was unclear where my bag was. Imagine my bag was off loaded instead of a potentially dangerous bag of a NON-boarding passenger! That bag flew along with us to Walvis and back. According to the same office the bags looked even differently! So much for security... After 1.5 months no apology, no response on my complaint and no compensation for being without a bag for 24 hours and the associated cost of staying the night. The office thinks that because the bag came on the next flight it is OK. Imagine if the next flight was a week later!