Deceiving Khulula.com discounts

I recently booked via tickets via Discovery Vitality and Kulula.com. What a horrible experience.

Before payment the website specifically mentions what I will be charged. Once I hit the pay button this amount increases by R150 and more!

I booked a flight, the amount to be charged was R1225 the actual amount charged was R1386

This is ridiculous, and I feel completely fooled.

I will never book with Kulula.com again and I am very disapointed in Discovery for not picking this error up.