Really Fast-Mail? Of South Africa Post office

On 14 September 2015 I send a A4 Fast-mail envelop from Vaalpark Post Office after a conversation with the attendee to make sure my post will be reached it destination asap. I were been told it will only take about 4 days to Levubu with fast mail. After 8 days I did go back and ask why my post did not arrived at Levubu. I then were told to just wait a few more days. I did so. I did go back again and then I were told that they can't trace this post. I then paid for a courier to send another envelop to Levubu. The first post only reached levubu on the 3th of November 2015. I want an answer to what had happen? It has cost me R15 for the Fast mail envelop + R93 for the courier + my petrol very time to and back from the Post office + calls to Levubu every day. Sorry it only took 50 day's!!!!! what happen.