Contract Cancelation

I currently have a contract with vodacom that is ending this month and I called vodacom in September to cancel my contract and was told that I need to call back on the 1 November to cancel. To my surprise vodacom has charged me for this month which is what I was avoiding because I know you have to give 30 days notice but the agent I spoke to told me that I need to call in November. Today i got a different agent which told me you have to give 30 days notice to cancel. I'm not happy with the service I received and the fact that I must pay for something that I called to cancel but was given wrong information. I wonder if your agents are trained differently or what? I'm not willing to pay what you charged me for this month because I called and your agent gave me incorrect information which is not my fault. I need this to be be sorted ASAP