I want cancel my contact as I'm not happy with their service.

Month end of October my Telkom debit order went through my bank account,later returned back into my account,and i was charged R61-00 penalty.Few days I received an sms saying my account it's an earrears i then called Telkom and i was told to go back to my Bank for answers.At the Bank they reversed the penalty fee and told that the was no need for the penalty as the was money in my account.After 9 days I received my Telkom statement showing that my account is paid and up to date.On the 13th another debit order went through with double installment of R478-00,unfortunately I dont keep money on Bank account the was insufficient fund and again i was charged R61-00.On the 16th my contracted was suspended.Yesterday I called Telkom and the Consulatant could not help with my query,I then tranferred R478-00 into Telkom Absa account.I called Telkom to ask what's next after paying.The Lady who was helping told me she cant help because system was down!I then went to the Branch today and I was given a landline to call the billing and account Department.The Lady by the name of Happiness Khanyile was arrogant and rude.She kept quite not giving me the answers and hanged up the call when I insist that I want to cancel my contract and speak to her Team Leader as she cant help me.I dont want Telkom service anymore I also explained to her that the network is very poor when I'm always home.