No feedback or response from MTN

In April 2015 I upgraded my current data package to a new wifi device offered by MTN. For the previous 2 years we had a contract for R149.00pm for 2megs of data, we never exceeded the data usage over this period. When I did the upgrade with this new wifi device we suddenly consumed huge amounts of data that i actually reverted back to the old device which stabilised the data consumption to previous levels. It took me about 9 months to get MTN to pass a credit for the huge amount of data that was consumed by the wifi device. In the meantime i had asked MTN to cancel the new contract as there must be a fault with their device or their systems. I was informed i must pay the account in full before they can cancel the new contract to which rep**** why must i pay for the data when it's a system problem. In the meantime MTN had a strike and you could not get anything done for months. I subsequently stopped using the data contract. In Feb 2016 i contacted MTN to try for the hundredth time to sort out this account and was informed the acc was with the legal dept. I was given a number ***, this no is continuously engaged. I got another no ***, here you just hold on forever.