Vodacom contract

Vodacom staff they are untrained when it comes to sales 🙄 how can such a big company hire people like this. I took a phone contract and I was told that I can settle the amount at any time and they Will be no charges now that I'm trying to do that it an issue, I have to pay the phone's amount and like 80% interest of the phone's amount... Once this is over I will never use Vodacom again