TOPTAP Mastery

I was recently billed for a subscription I was not aware off and I did not subscribe too. Its called Toptap mastery which charges R15/day, I called MTN customer care and they told me where to check and how to cancel it. This is very poor service from MTN and very suspicious to me as it does not even reflect on my billing info on my app which i monitor frequently. I think this is some sort of a **** from MTN which needs to be investigated.