Vodacom - Ignore queries , but spam calls you !!!!!!

I emailed customer care a week ago advising them that an unauthorised "airtime advance" was levied on my account. To date , I have had no response from Vodacom. They obviously spend far less resources on customer query resolution than they do on unwanted spam calls. A day or two ago I answered their call as I thought it was to resolve my query, but it was a marketing call. I told the lady I am not interested. Today i am receiving these marketing calls again. Do they not put a note on the system after you tell them you are not interested? Why cant they be they put this much effort in their customer care line?