Abuse of data

My data usage kick in on 1 June. By 6 June 2015 12 I received a notification saying that 80% of my data was used. Tried contacting Telkom about it and did all the run arounds I was sent onto. By 18 July we were reconnected after lots of screaming and shouting and using HelloPeter as a last resort. I'm back here because 80% of my data was used again, but not by me . I made contact with Telkom regarding unused data, and is still waiting on a reply. Does Telkom have no other competition on the communication front,because I can't do this anymore. As a pensioner,I am reliant on the Internet to stay in contact with my children. Not good service