Hidden Cancellation Fees and No Honest Notification

I called Cell C and gave 30 days advance notice to cancel a consumer phone contract.

Contract end date was 10 June 2019, all charges should of ceased 10 June or continued until month end with the same monthly benefits and costs as the cancellation agent explained to me over the phone.

To my surprise, I receive a June statement with an additional R500 which I did not agree to nor was I made aware of. I find this utterly unacceptable.

Please get back to me urgently to resolve.