TERRIBLE CUSTOMER SERVICE

I have just had an unbelievable customer care service with MTN South Africa( consultant Sthembile Ngwane).

I called this morning to cancel my contract. She was irritated from the moment she picked up the phone. She was impatient and very rude. She then got angry at me for not remembering an MTN pin. I asked her why she was rude and she asked me to hang up. I could not believe it. I could only ask for her name. I see the same consultant has had a complaint https://www.hellopeter.com/mtn/reviews/cellphone-contract-application-***

Why does MTN tolerate this?