Absa mega u benefits

My son has an account with absa, so he receives monthly vouchers. But the problem with the vouchers is that when you redeem them they tell you the vouchers have already been redeemed or when they give you a pin its invalid. I emailed the email address they provide on the sms'they send. But all I received was the same email from the different customer care people. That they have received my query and will get back to me within 48hrs. Something that never happened. So in actual fact there are no benefits because my son was only able to enjoy it once.

Tour service sucks absa