Telkom potential theft

Have a Telkom mobile contract which I ensured had a R0.00 spend limit . This was suddenly activated and I received a bill for R1000 more. I went into the office and they called the call centre on the 28 sept 2017. I spoke to Sherillee Mangeo who then gave me details of the manager that then resigned. I then emailed Charmaine Ma***o the manager, who initially responded and is now just ignoring my emails. Spoken to Lindokothle Nkagana as well ad Ayabulela Gagya and to date still no response. They all refuse to give me management details and even the CEO is secret. Service means ignore them till they go away.