Vodacom over billed me

Got an SMS to say i need to pay an amount in next 5days - but i paid - phone call centre only got answered 35min later and call dropped in next 10min - i told them i cancelled the insurance on the one number on 1/7 - but was still fully billed on their side but not on App - so after i phoned the one numbers Bill so far changed from 284.9 to 425.59 - i wont take this from vodacom i got a letter to say insurance was cancelled but they billed still like normal and after the call they start to do things on app - i will cancel my 2 phoned with them if they do things like this!