The worst service from Telkom

I bought 1 Gigs worth of data yesterday at around 15:57 and I received an sms at 16:06 that I had 510MB left and I wasn't even using my phone at the time and at 17:39 all my data was finished. I called after I received the first notification and no one helped me. I was told to call this morning of which I did and was told that the internet finished my data. I do not understand how because when I got the notification that my data was finished, I was driving so I do not understand how I could lose all my data like that. I am very frustrated and disappointed at the assistance I received this morning as I was given no answers. I can't keep buying data if I do not know where it ends up. I have tried contacting Telkom via Facebook, email and even their helpline and I keep getting false promises. I’m very disappointed at Telkom. The consultants tell us that they will contact us back. I have been waiting all week. It’s tiring and very disappointing