Changing Flight Boarding Gates and not informing the passengers

Good day,

I would like to log a complaint against for a flight that we missed - SA264 from Johannesburg to Munich.

My colleague and I were supposed to leave on Monday the 13th of November to Munich. Our original departure was in Port Elizabeth and that is where we checked in for both our flights - the one from PE to Jo'burg and Jo'burg to Munich.

We departed PE for Jo'burg and our boarding gate as per our tickets was A0006. We got to our boarding gate at 20:45 which was our boarding time. To our surprise, there were no passengers at the gate so we decided to ask a security about our flight.

He then referred us to gate A0022 and told us that the gates had been changed. We were not notified of this, not bu phone or email.

Unfortunately when we got to gate A0022 they had closed already and we were then told to go to transit for our luggage. When we got to transit we inquired about this and we were told that, that was the last flight for the day and we would have to re-book for the following day at our own cost.

How is this possible? Why would they not notify us of the change in gates ahead of time? Why did we have to cover the costs if they had made the changes and did not inform us?