Cell C unable to cancel contract

I am at my fifth request to cancel a cell c data contract. My 24 month contract expired in May 2018, after which it increased from R99 to R260, after noticing the increase I inquired, they indicated that due to the 24 month contract came to an end they reverted to "normal rates". Firstly since when do you just increase a contract rate. I contacted Cell C on 084143 to cancel the contract Cell C on 19, 30 June 2018, also on 6, 17 and 30 July 2018 and again on 1 August 2019. That is six (6) false promised to cancel a contract. What more should do? Can someone that has some integrity left please resolve this matter, last ref was 1807 ********** 2 and the operator was Piet, he to promised to call in 48 hours, left a message on 1 August 2018 with Lance for him to call me back.