Vodacom horricfic service

How is it that Vodacom can't get it right. I have changed my contact details with them numerous times, giving them the main contact number for my contracts. Still they phone my underage daughter. I have opted out and is not registered for marketing and yet they phone her 4 times a day with sales offers. And everytime the contact number is incorrect on my account. Last change requested was the 9 of September and again today the same problem, phoning my daughter with sales having all my account information. How many times do I have to request the amendments. And how is it that the details can be altered back to original details without my approval.