Vodacom Contract Renewed without permission

I left South Africa in 2018, I still had a contract with Vodacom which I paid each month, this contract should have completed in 2019. They have been auto-renewing the contract without my permission.

I have tried to use their online chat and phoning their call center, but at 8:05am apparently all consultants are busy. I followed all the prompts on the phone only to have it disconnect me.

I'm not sure how they are allowed to renew my contract multiple times without so much as speaking to me or how I can cancel this contract now from overseas