Vodacom remains locked in - public cannot reach them

I have since mid May 2020 attempted to cancel a contract. I have attempted to reach them via their client call center number "135". Your call is never answered. Eventually once you have listened to all their electronic jargon, the electronic system allows you to request a call back. Do no anticipate a call. It never happens. I also attempted to raise my query via Tobi, their bot, answering queries. Again unsuccessful. Lastly I forwarded emails to their e-mail address "***". I received the numerous read receipts, but still no acknowledgement or engagement from their side. Vodacom, please note I want to cancel one of my contracts, you were given notice, and elected not to respond. I will destroy the sim card at the end of the month, and will no longer pay for this account