No response to request for exhorbitant billing

I was charged a massive R3 459.34 for using 3.5gigs of data out of bundle and requested a breakdown of these charges on 2 separate occasions, but to date haven't had any response from MTN. They are simply ignoring all attempts to get a cost breakdown of their charges. I keep getting a reference number and a promise that my query will be attended to within 7 days, but this just never happens. I have called the call centre and also sent emails through my MTN portal, all to no avail. Could someone at MTN please help me, please! Is this how you treat your customers?<br> The latest reference number I was given is ***.<br> It seems my last option would be to go to ICASA if MTN continues to ignore all my requests. This is just so sad and pathetic for MTN to treat it's customers in this shabby way.