Cell C never cares about their customers

I had a contract with them and they didn't tell me that I have to cancel it before it's fully paid, okay fine.. But what they did they charged me the same installment, and told me that since I didn't cancel, it automatically becomes the month to month, but what puzzled me was, why do they charged me the full installment because I'm 100%that I now only pay for Data that they gave me, why they still charge me for the cellphone that is fully paid up? I did then canceled on the 10th of August but still they charged me for this month even though I canceled. They told me that they only remind customers of what is due to them not what is due to customers when I asked them why they never reminded me that I had to choose if I wanted to cancel the contract or be in a month to month agreement... I'm so disappointed shame and this is not the 1st time they disappoint me