Activation of service without my consent

I have two contracts for my kids on my name. After about a year a data bundle was added without my consent (This cost me R400,00 per month). I phoned the call center to query this and to find out who authorized this and they couldn't tell me. I logged a query (***) and they said that I would get a SMS or a E-mail but up to now a week later I have not heard anything. When I checked the reference number on their web page it shows that the complaint was opened and closed on exactly the same time. So this tells me that they didn't even look at my problem.