Over promise under deliver

Telkom once again over promise and under deliver.I recently posted this and upto date no response from telkom.I upgraded my adsl package to the to a 24 mnt contract i was given the modem,this package also includes a lit box off which now is going over a month and no response as to when i will recive it.The call center keep saying theres no stock i need to just wait.this is not how a buisness should operate if u advertise a product ,it should be able to deliver to the comsumer.i had enuf off telkom,if any one could assist me in cancelling the contract with them it will be much appreciated.