Vodacom divulging personal info and encouraging ******** activity

Vodacom gives out your number and personal information like your name and the status of your contracts to third parties. In my case I am overdue for an upgrade. I get calls, sometimes daily, from people claiming to represent Vodacom “informing me” about the status of my contract. No way to get them to stop, and recently it has begun to border on harassment. Yesterday a woman called and was very rude when I asked her to stop calling, she hung up on me too. Today they called again at a very inconvenient time, when I realised who they were I said “please stop calling” and hung up, they proceeded to phone me back 5 times in a row! I am quite certain this is *******, definitely a violation of POPIA, and probably grounds for class action if others have experienced anywhere close to the same treatment as myself.