Unauthorised Debit Order

I app**** for a new bond through Better Bond. After approval I received a call from BetterLife regarding structural insurance. I am hearing impaired and don't do telephone marketing, but I was under the impression that the call was from Standard Bank and the insurance is a requirement. A agreed to a policy, but as soon as I realized my mistake, I cancelled the policy. I have written proof that I cancelled the policy on 27 July. I received notification that a BetterLife consultant would contact me, but no one did. I sent another cancellation email on 28 July, again with a notification that someone would phone me. No one did. On 6 October I sent another email stating that no one phoned me regarding the cancellation and that I will not allow any deduction from my bank account. Now they have deducted R220 from my bank account for admin. The house isn't registered in my name yet, so no insurance is required. And in spite of numerous attempts to stop the policy from activation, they deduct money from my account. What more do I have to do to cancel the policy?