Vodacom's 2GB + 2GB Night owl a reap off

I stayed late (after midnight) on the 17th March 2015 just so i can use my 1.96GB night owl data and spare my normal 1.69GB data. At the end of my session around 2am when i checked my data balance, I still had 1.96gb night owl data and just over 600gb of normal data. Meaning that Vodacom was busy billing me from my regular data even though i was surfing the net between midnight and 2am. I want to know if this vodacom night owl data business is false advertising? If not, then i want my data refunded.