Line changed to open line w/o authorization

Being a Vodacom customer for over 6 yrs with 3 contracts, I am rather disappointed with the service received by Vodacom. I have lodged many complaints with the Vodacom consultants and no one was able to give me a valid reason or explanation as to why my 3G sim had suddenly been converted to an open line without any notification or authorization. All I was told that my 3G sim is an open line. Having explained to the consultants that this was not always an open line,and that I did not authorize an open line, I was informed that they will look in to it. An entire month has passed and I have not yet received any feedback relating to my query.<br> I have had a 3G data contract for almost 2 yrs & whenever the 2G data had been depleted, I was unable to connect to the internet. In December 2015, this was not the case. When my data had been depleted, I was still able to connect to the internet, having no notification that my data had been depleted, I was charged out of bundle rates. I find this to be extremely strange as every other month, if data had been depleted, a connection could not be made. A webpage would open up stating you have run out of data. Meaning that the line was capped.