Vodapay competition

There was a promo competition running on the vodapay app for goal rewards, I completed a goal and the when I tried redeeming the reward it showed me an error message I contacted vodapay but they couldn't assist me I was sent from pillar to post for 3 months without any assistance then I got a response saying they going to give me 500 vodabucks as sign of good gesture because the reward was either allocated or it has expired . I'm not happy with the resolution can someone advice what to do to lodge a complain with the competition commission of south africa or ICASA because in all honesty it's not my fault that the reward has expired as explained . I believe if I was assisted within the promised turnaround time the issue would have been resolved