Wrong amount billed

They haven't sent a statement since February 2015, I am always billed for R1026 now I get billed R1089 in May when I call to ask why they tell me I requested for data that I don't even know about which is impossible when I hv the top up contract. Apparently u called on the 17 April requesting this when I request for my conversation they say its impossible that I get it. At the call centre they sent me from pillar to post where I spent over 40 minutes just to get my case registered to be investigated. This is not the first time for 2 months I didn't get my promotional data they say I spent it the all of a sudden 5 days later I get an answer to say it's being loaded but no one called to apologise. I am sick of vodacom service and rude call centre people, I will be moving my contract and if they don't give me the recording I'm taking them further up all they know is to be rude and do false advertising to attract clients. After 4 years of a contract they are going to lose a loyal customer I'm even going to terminate my prepaid and move networks