Changing my information without my consent

I am not satisfied in the manner that Vodacom has changed my personal details on 19 March 2015 without my consent. After investigating with Vodacom it was established that someone has changed my personal details, physical address as well as e-mail information on Vodacom's systems, How can Vodacom just change my personal details without me even contacting them? Without me even knowing about it. Every time I contact Vodacom I am being sent from one consultant to the next. All I want to know is WHO changed my details on their systems and no one at Vodacom could tell me. My reference number since first call made on the 4th of June 2015 was S3-87G3X-XRRGC,I then called back on the 8th of June 2015 and said they are still investigating the matter, I followed up again on the 9th of June 2015 without any success. Then on the 16th of June 2015 I received and SMS to say that it has been handed over to CIC for further investigation. Vodacom requests documentation from me to rectify Vodacom's mistake. I will be taking this matter further with my attorneys to subpoena Vodacom's records to establish who changed my personal details without my consent, I expect answers to my request