The Telkom Monster

I have no contract or obligation towards Telkom/ I urgently require their Legal Department or Senior Management intervention (or simply someone that "wants to"): I all of a sudden keep on receiving calls and sms's out of the blue for an "unpaid account" (with associated risk of arbitrary 'blacklisting' which we so quickly resort to), also all of my details having been shared with a 3rd party in contravention of POPIA? And yes, I have called, subsequently e-mailed, follow-ups - NO RESPONSE. P.S. Upon calling, I have actually been advised that Telkom owes me approximately R1100!! HOW DO I STOP THIS SCOURGE?!