Charged for postponing the Trip

Good Afternoon.<br> <br> I bought a ticket from Intercape on the 19 of August 2015 for departure on the 20th of August 2015. I then went to intercape on the 20 th in the morning to postpone the Trip I was charged R60 for the postponement.. i ask Why i was told i was suppoed to arrive at 7:30am to avoid the payment, the amazing thing is the intercape offices are not oopen at that time of the morning.