Debiting money but I'm not using their service

I bought a rain sim card, for unlimited data n I had so much challenges with it there was no coverage, I called and I was told that they were busy upgrading some stuff, I ended up deciding that I should quit this service, because I am paying for nothing, I called the service provider and I was told I should cancel a month in advance, I did that as they said, I should go into their website. To my surprise this is the 3 month they are debuting R469 and I'm not using their service, I would like rain to explain to me as to why are they taking money and the contract is canceled.