Poor and lies from vodacom

Poor service from vodacom, last month I was going to cancel my contract as its due to end however a consultant convinced me to keep the contract on a data sim for 179pm where I get 20gigs day and 10gigs night. It was a promo they were running at the time. However this morning my account balance shows 10gigs day and 10 gigs night and this isn't what a agreed too. I have called them but the service is useless as they are telling me that on there side its shows 30gigs but they cannot email any proof regarding this. I have requested them to cancel my contract as this is not what I agreed for and the comments are we log your call but cannot send you and email or sms to confirm. What nonsense. I'm canceling all my contacts with vodacom.