Kulula, despicable conduct. Are you really desperate for money?

I paid an additional R130.00 to choose a front isle seat. Last night my boarding pass on the app still reflected the correct seat. When I checked again this morning it had changed to a standard seat. I telephoned Kulula asking what exactly had happened. The lady gave me the standard " we had to change planes" story. I said no problem, just return my R130.00. After an argument, all of sudden she 'found 'a middle seat in the front. I had no choice but to accept that. Strangely enough that was one of the seats that was also available when I booked a week ago. Further a friend of mine who chose her seat last night still had the same seat. Really Kulula that is despicable. I would never have noticed the change of seats until I arrived at booking in, and that would have been too late. Thus Kulula would have earned an additional R130.00 by booking someone else who would have paid the additional R130.00.