Complaint: Data Vanished

I am very disappointed to learn that Cell C, a network i considered to be far better than the rest of the networks we have in South Africa is now adopting Vodacom strategy of sucking the consumers dry of their data. Today in the morning I purchased 80MB data, but in a few minutes I received an SMS stating that I am only left with 36,94MB. I mean I never subscribed to any services on internet hence I fail to understand why my data is taken just like that. This is so disappointing and unfair judging from the fact that data is very expensive here in SA compared to most of the countries globally. I sent an email to Cell C as well as a message on their website regarding the matter but I haven't received any assistance. It goes to show that here in SA as a consumer we are taken advantage of, and we are given a treatment lower than the ground. It's a worrying factor.