Bad services and over charging

Did a early upgrade 6 months befor end date telkom gis you 2 months befor end date to renew i had lef 6 month ask to pay the full outstanding amount told me no i cant do that the need to take it by monthly now they charge me more. I did the ubgrade in November renewal was in May now they changed me 2 mont extra i never terminated the contract i renewed it they ar thefts will never let one of ma family or friends open a account with thelkom