Contract Renewed without permission

My father had a Vodacom contract for more than 10x years. He stopped upgrading his contract due to the terrible service he has received a couple of times.

Without his permission they renewed his contract for another 24x months. He did not agree to or sign anything, We have tried numerous times to speak to someone in Customer service who can assist us with how something like this could happen and to cancel this immediately but we get no response/feedback. No one can even tell us how something like this could happen.

Now he has to keep paying for something each month he did not want or ask for or even give permission for.

We want this sorted out with immediate effect. How can you renew a contract without a signature or permission? This is totally unacceptable. I'm disgusted with Vodacom. We need someone to sort out this mess immediately.