Vodacom overcharging me and not reachable to resolve the issue

I am very frustrated with vodacom. I took a contract with Vodacom, for which i was paying around 1700 a month including assurance. The attached insurance then expire on the third month. meaning i was to be paying around 1300 pm. I then took another insurance or 350 pm.

Right now, vodacom is taking 1700pm and another 700 per month for what i dont know. I have been trying to get hold vodacom with no luck. Frustrated.