What is happening Vodacom?

I have been with vodacom for years and have recently changed contracts and received a new number. The number I got appears to already be taken as I have received multiple sms's to two different people... Both of which are NOT me. I've received calls from random people too. I have also seen that my bill is more than double what it should be? Have I been charged for this other person's bills too?? I was also horrified to discover that vodacom now CHARGES loyal customers for caller ID??? This is a complete money-making scheme, I already spend a lot every month and I'm very disappointed by this.