Business ADSL Line Offline for almost 4 weeks

Telkom is doing their best to ensure that our Online business is incapable of operating. We are entering our 4th week now with our ADSL line out of order. To top it off, because the last technician could not even be bothered to test our lines, he made me purchase a new modem, when my last one was in perfect working order, when their lines were up and running. I am now told that I cant return the new modem, since I have opened it. So not only is Telkom not repairing my Business ADSL line, but they will not refund my almost R600 that they made me outlay erroneously. Does anyone have any suggestions as to how I can get them to repair my ADSL line?