Data charges

On 24 March 2016 I received and sms to tell me that I have reached R1800-00 of my "default" data limit of R3000-00. I immediately phoned the call centre an logged a query as my data is limited to what the package offers and once I have used all my data, I receive an sms to tell me no more data left. The reason being that I have wifi at home, work and I use public wifI if I need to. The reference number for this query is : A7-CZDE-38UI. I have not had any response to this query however Vodacom commits to respond in 48 hours. My query related to the fact that I want to know who changed my data limit to "default" of R3000-00 per month? If you look at my usage past 12 months you will see that I never use this amount of data. Strangely the sms's also stopped to inform me that I have used all my available data and I then excepted that it must be because I use wifi and home, work and public. When I then all of a sudden received the sms on 24 March 2016 to tell me that I have exceeded 50% of my R3000-00 "VOLUNTARY" call limit usage, I remember receiving a call from "vodacom" call centre to offer me more data. I clearly stated that I am not interested as this is a corporate phone and I am always in a wifi area. Clearly from there this is where all went wrong. Since I received no response from the query logged at the call centre, I phoned them with and "they are working on it". I then logged an online query on 10 May 2016 with a response that a Customer Care agent will be in contact with me in 24 hours, well still no response. In the meantime my company paid this bill and I have no control over it and vodacom clearly just ignores all queries. The same happened last year and I had t take the knock of a couple of thousand rand. I am now at point where I want answers on what is the in-house problems they have and why does it happen that my data limit can jus be "changed" without my approval or knowledge.