over billing and worst service

in December I got a call of a good deal - Cell C got a contract for R99 for 5 GIG's<br> come January, they charged me R2433.28, stating that we went over.data bundle finished so we went over to normal internet usage. My first question was how is it possible as this is a data package? after this, for the first time I was told this is an open account, but they will investigate, Lady I spoke to name was Malebu, she even spelled it for me, never the less, she advised they will investigate and come back to me with in 2 days - this was on the 18th of January. on the 29th of January I phoned again to find out what is going on and spoke to a lady called Fortunate, who advised there's nothing she can do and I need to phone their accounts people, who I believe is on the same number. so I asked to talk to a manager and was told this is not allowed as I need to talk to the supervisor first, and then only I can talk to the manager, so I asked to be put through but could not as \ Shelvine\" the supervisor is on another call but will phone me with in 10 minutes. today is the 3rd of February and still have not received any calls, not even feedback on what is going on. REF *** refers."