Breaking promises

I have been a loyal customer for almost a decade now but MTN doesn't even try to help & give me feedback on what I asked for! First off my contract ended 5 months ago and because they didn't notify me I am paying a huge amount each month for nothing but 500mb of data(the device is already paid for as per contract). Now I am trying to get info about buying out another contract and all I get is empty promises and automated responses!! They say they don't want to lose you as a customer but offer no service!