CellC don't want to cancel expired contract

My contract on *** expires on 9/9/2015.On 3/8/2015 I called cancellation dept.They told me in July I must call 2/8.I spoke to Thabiseng and she told me the contract expires on 9/9 and that all data that was given on 1/9 will lapse.She gave me a settlement amount of R311.63 that must be paid 1/9 and that I must contact them after payment to confirm.I have paid yesterday and when I phoned this morning they told me the cancellation was no put on the system by Thabiseng and that the contract will go on for another month and that I had to pay again end of this month.I want this contract cancelled as originally arranged on the 9th.I can't keep paying for someone that can not do her work at CellC.The lady told me this morning that I must use this settlement amount as a credit and pay the rest end of the month!Why?Pathetic!