KLM pathetic

I booked business class tickets online no problem. The tickets were flexible and when we wanted to change the dates the website which pronounces with much fanfare that you can just change it online said that I cannot do it online and must contact their customer services. After a mission I got in touch with them and they charged me R30000 more for the new flights (no change fees - just fare differences) although I could buy the sane flights online for only R5000 fare difference. They insist that my booking class is not available fir the new dates and that I must pay for a higher class but on the website I can still get the same business class tickets at only R5000 difference. This is ******* and I will report them to the competition authorities.