Robbing "Peter to buy Paul" ??????

Just a short one..... will get on with the details later... Pont #1, not my first run in with SAA, nor the last... sadly sometimes there's NO choice but to use them. I booked a ticket in April, had to cancel the ticket - (Mother's healthy issues = have documentation etc....), cancellation was done in due course blah blah blad So I opted to use the old ticket's details / reference for a new booking, as the old ticket is still usable / valid for 12 months, I am aware of the taxes + penalties, hence I am cool with that. The initial ticket cost me +/- R 5200, I got a reply from SAA (via my agent), should I wish to use the old ticket, it will cost me another R 6000 !!!! Do the math, a R 5000 ticket becomes a R 11 000 ticket. Well, then we checked and a new ticket - new reference (same routing) only costs R 5200... Can SAA please explain this??? Or perhaps I am blind? but.... certainly not stupid. I will give SAA a chance to figure out what to do, as this will not be left aside by me... I will get my refund... not 100%... but what is due to me...