Can so much really go wrong with one flight!

I arrived at Cpt Airport 2.5 hours prior to a domestic flight to Joburg and went to the Mango check in counter. My ticket was booked through SAA but operated by Mango. The flight number was SA2017 departing at 14h15. At the check in counter, the staff had no idea which flight it was as they didn't have one leaving at that time and they redirected me to SAA. The line there was long and it took an hour to get to the front only to be told to go back to Mango. When i got back there they spent 10 minutes checking their system and eventually said that i was on flight JE158 departing at 13h55. Thank goodness i had arrived so early or i would have missed it! They confirmed i had a meal voucher and wrote this on the ticket. On boarding the plane, a gentleman was standing in the front who had been assigned seat 1A... but the aircraft only had seats 1D - F (1A-C didnt exist) and seats so small my neighbor couldn't fit in! When i tried to claim my meal voucher i was told it wasn't valid, so i paid cash and asked for a receipt which i was told wasn't possible. Then the final straw. Arrived JNB and a carasol wasn't assigned until 15 minutes after arriving into the baggage reclaim. Never Again!