Vodacom Contract unfairly billed

I took a contract with Vodacom for R295 , sometime last year for the first 2months was charged correctly, thereafter i got charged an extra R173.00 on realisation i called Vodacom call centre early March was told by the agent that was paying for data 3g which i did not sign for she told me she was going to cancel ,Then today the 03.04.2020 i realised my bill its still high i called the call centre again and was answered by a lady callled Mohlatsi who advised me that am still paying the R173 EXTRA meaning it was never cancelled on futher talk to her she told me that the first agent did not do her job properly she did not cancel.Please avoid Vodacom contracts at all cost