has cell c turned in to vodacom by taking ones airtime

i never thought that i would experience this with cell c as well. just yesterday i recharged my account with R150 airtime, which is something i have done so many times before and the reason why i moved to cell c. the airtime together with its freebies last me a long time because i make calls to cell c numbers and i switch of my data when i am not using it and i have never had to buy the whatsapp bundle. this is how i use my free data ( 400MB) to access whatsapp and occasional receiving of emails and switch it off. This time around i am shock, i normally check my balance so that i don't exceed what i have, by the evening of the same day i recharged i was left with less then 200 MB and my airtime was at R 110.00 with whatever cents . you wont believe what my current airtime balance is as i am writing this review. I am sitting with R 0.00 balance mind you i have not made any call whatsoever the only thing i have bought is the whatsapp bundle of R12 and my 400MB. Can some please explain this scenario because i really don't understand what is going here. should one stop and look for better reliable networks?