Selected network (Vodacom-SA) unavailable

I have been with Vodacom for a few years now, and never had any issues with internet or voice connectivity issues, but ever since I have upgraded my contract in December 2014, I have endless hassles, connecting to the internet, and make voice calls.I did report this before (00RQ~QXXK) and I was informed that Vodacom does not have a network issues, but it maybe that I have a faulty sim card. I did replace the SIM card at a vodacom shop in Centurion, but still with no luck. I still get an error on my phone \Selected network (Vodacom-SA) unavailable"This happens all over Gauteng"