Unbelievably appalling service on cancellation and billing by CellC

I'm so appalled by the lack of service and trickery of cellc. When my contract was nearing it's end retentions department kept calling me and one cheeky lady was trying to pressurize me to upgrade. She was actually being sarcastic with me about how I need to listen to her because she is not from the sales department but from retentions. My contract was ending on 22 June and they told me that I must call on 31st to cancel. I decided to call on 25th June. Then they told me that I was supposed to give one months notice before cancellation. I think the cheeky lady from retentions misled me on purpose si that i do not put in my notice on time. I was told that my contract will be terminated only end July and I will be liable for July and August subscription as payments are in arrears. My contract was for 20G at R269 but now the promotional data would fall away and I would only receive 10GB at a rate of R320. I discovered in August that the cancellation was never done and I emailed cellc. They are now informing me that the cancellation will be done end of August and that I will be billed for September after cutting the data at that. Is it my fault that they are tricking customers to remain in contract with them with such underhanded schemes? They want to get out of me R960 for 30GB of data when I am paying R299 with MTN for 50GB a new contract I took out because I thought this one would be cancelled. Who robs and misleads clients like this and still expect us to do business with them in the future or recommend our friends and families? I mean are they that desperate for business? I told them to release the call of 25June when I cancelled since all calls are recorded when they sell us these contracts but now they cannot release the call. I asked them for a number for their compliance department and when they call me they pretent not to hear me and cut the call. The lady who did not do her job to cancel this contract on 25 June must pay for that bill not me. I will be taking further action against cellc if this does not get resolved soon. I'm disgusted by your service and desperation to make money off clients, this company is leeching off vulnerable people..