Unresponsive in resolving dispute

I Have been trying for almost 2 months to resolve a dispute around billing with MTN. The organisation is unresponsive and doesn't respond to complaints in the allocated time frame.

I know that I will never get this resolved and would take this legal, but am aware that this will never get resolved as I am just a little guy trying to fight a large corporation. I wish that their business would be given the same service. If it was it would come to a stand still.