Incorrect charge for data

On March 24th I phoned vodacom business to report incorrect data charges on my February Invoice. The SR reference for the call is A1-XOFK-CE Q123 and I was informed that they will investigate and resolve the issue by the 24th April. I kept calling to ask about progress and why the people investigating are not contacting me as promised. I was then informed that the matter is now scheduled to close on the 4th of May. I kept phoning and requesting that someone contact me with feedback and Finally yesterday I got a call from Amber who offered to pay me 50% of what I claimed as incorrect billing for data usage as they cannot go back in their system to retrieve what the data usage was for. I found the offer to be baseless and inappropriate as it is made to be goodwill from Vodacom and ignores the fact that taking it is at a huge loss to me. If vodacom cannot prove what i did with the data the right thing for them to do is pay me back and not make their system issues my problem. I'm very disappointed by this approach and the fact that incorrect billing inconveniences someone financially does not seem to be an issue for Vodacom this was displayed by how I was ignored for a month.