More money debited on my account

I have a contract with MTN for two lines, one line is for data bundles. for both I was paying R740. My contract ended in June & I called the retentions department to cancel, the first agent I spoke to was rude and said it will be cancelled, to my surprise on the 01st of July an amount of R118.60 was debited. & again on the first of August, today I called again the retentions department they said my contract is still running month on month. and she said on the system it doesn't show any records of my previous calls for cancellation. I asked to speak to her team leader and she hung up on me. still with no resolution