Charged out of bundle rates

I requested a dual sim from MTN which I wanted to use for data. After using the sim for a few days and checking the data available on my contract I noticed that the data was not depleting. I contacted MTN more than once and was told that this was not a problem and that the data depletion does not always show when using a dual sim and was assured that I would not be charged out of bundle rates for the data. <br> <br> Low and behold, when I got my account I was charged out of bundle rates. I logged a query with MTN and was told that the reason for this was because when I used the dual sim in my router I did not disable data on my phone and therefore were using both sims on the data network at the same time and would be charged out of bundle tariffs.<br> <br> Now, I have a serious problem with this as I did contact MTN when I did not see the data being depleted but was assured that the dual sim was working properly and that I would not be charged out of bundle tariffs. MTN could not provide a reason why the data was not depleting and did not tell me that it was because I was accidently using both sims for data at the same time.<br> <br> Greed and compentence!