Cell C - worst ever!

On the 1st of June I received R200 airtime from Cell C. By the evening of the 1st, the R200 was depleted. Naturally, I phone Cell C for assistance because I know for a fact I did not finish so much airtime on a few seconds of Instagram and 3 downloaded songs. I get put through to an unsympathetic woman who tells me I used my airtime and I should wait for July before she can tell me where that airtime went. She dismisses the fact that I tell her I didn't use R200 worth of airtime in a day, rudely telling me to increase my limit if I wish for more airtime. After hanging up, I phone costumer service again and speak with Rebecca, who is helpful and logs a query for me, agreeing that R200 airtime cannot disappear in a day. She promises 24 working hour response. 8 days later ... when I've not received a response from Cell C, I give up and life goes on. The evening of the 13th June, an abrupt and unhelpful call from Yudesh at Cell C comes through, offering me an upgrade. An upgrade??? What about my Query??? Yudesh proceeds to tell me, and I quote - "You have a smart phone, even if you do not use your phone and NO apps are open, R200 airtime can still be taken." I am angry, and tell him I do not want to upgrade, and when my contract is up, I will be cancelling and Yudesh tells me, and again I quote - "You do that..." Wow.