********** no refund or change

I've mistakenly booked a flight for the 25th August 2017 I meant to book it for the 26th as the flight is early in the morning. I phoned to change and was told I had to pay a service fee of R 300 extra I already paid R 492. The flight for 26th is R 600 and something . Now I have to pay an extra R450. And if I cancel there will be no refund