Charged More Than Agreed

I gave Vodacom a chance but I ended up regretting it, Vodacom has charged me R1980 for a R449 contract. How did we even get to 100%?? They said I need to check on my itemised bill and surprisingly the bill keeps showing me that calls made charged R0.00. A contract with 50 minutes and 3 calls made and I’m being charged R1980?? How? I’m not happy with the service and no one can explain to me how we got to this amount. I’m very disappointed in Vodacom and I will never ever recommend anyone else to take up a contract with them. Definitely not reliable and they are ****mers.