Highly upset customer - Contracts not being cancelled & No deduction on deduction date

I am highly disappointed with Vodacom. My account was behind for the 4 cellphone contracts I have with Vodacom. I've than got my account on track 2 months ago where I had to call in and I had to ask Vodacom to check and confirm this and I requested for them to create the debit order again, which to my surprise seems like it was never done. I have also asked Vodacom to cancel one of my contracts as the contact ended and I am not willing to pay month-to-month as the contract is no longer required. I was transferred to the cancellations department and no one answered. I have tried numerous times to get through to Vodacom to ensure that the contract gets cancelled but no one seems to answer. I have received invoices from Vodacom which stated that there is no outstanding payments than I got another one stating that there an amount of R875 that will be deducted on my next deduction date and to my surprise, it was never deducted. now I am sitting with a bill that is way over my budget all because of Vodacom not following instructions and not answering my calls. I am highly upset with the service from Vodacom and it seems like i always have to encounter such issues with them.

Can you please arrange for the bill to be rectified I am not willing to pay the amount that is stated on my account as it is not my fault that you guys did not deduct the premiums on the deduction date and that you did not cancel the contract as per my request.