Telkom is a Terrible Service Provider

I am extremely annoyed with Telkom. I upgraded my contract in November last year. My upgraded cellphone was ****** in February and when I went to go and claim for the phone, I was told that my old phone was insured and not the new upgraded phone that was ******. They for the first time tell me that I needed to tell them when I upgraded my phone that I wanted to move my insurance to the new phone. I was with Vodacom for over 20 years and I never had to separately move my insurance over. And the fact is that no one mentioned this when I upgraded. At that point I ask if I could cancel the insurance on my old phone and if it was possible to cancel my contract as I no longer had a phone. I was told to send a query through on the site. Which I did. I spoke to the insurance and confirmed that i wanted to cancel my insurance as the wrong phone was insured but i never heard back from anyone about cancelling my contract. After that i bought a phone and continued to use the contract. Yesterday i received an sms to say that my contract was cancelled and i owed just over R8200. I never once approved or agreed to pay this amount. Even if i did send a request to cancel my contract, i did not once approve or agree to pay the amount of over R8200 to have it cancelled so how can this be processed without my approval? I called in and was told that there is nothing they can do to help me and the amount will come off my account with the next invoice. This will cause all of my other debit orders to bounce. This is completely unacceptable!