Unauthorized debit orders

These been some unauthorized debit orders on my bank Account for the company named Telkom on the reference and this issue has been recurring and this is almost the fourth month happening. i tried making an affidavit at the police station and sent all the necessary documents to Telkom for some investigation but this issue has not yet been resolved because yesterday they took another R2500 after my salary was paid to my account. last week on the fifteen this unauthorized debit order took place but my account had no money s i shifted my funds on my savings account and this resulted in unpaid items fees which at this moment has culminated to over a Thousand rand including the previous months fees of the same stock. Inquired constantly in my bank for help and also trying to reverse the unpaid items fees but was not helped and i also wrote to ombudsmen but was referred back to my bank for help, that did not help at all as i was told it was my responsibility to sort this out. I MADE ALL THE MEANS POSSIBLE to sort this issue but was not helped and this has caused me extra costs excluding bank charges and other related bank fees. their response is Telkom is the big company and cannot do such. my rationality was why don't they prove the rationality of my claim and acquit me from all fees and costs related.