Unhappy

I took two contracts for my niece and my mother in 2014. I have been paying for the two of them until February this year. They debited my account again at the end of March regardless of having spoken with one person about the cancellation. When I enquired they told me it was because they uploaded airtime in March. When I asked my niece and my mom about it, they were shocked about the airtime because they never got any airtime from Cell C, since the beginning of the contracts. I would like to know what that means and I would like to know what they debited my account for in March? I am very angry with Cell C, their network is **** and the only thing they do is take money from my account for a terrible service!!