Telkom Data disappaering and no customer support available

On Saturday 16th Nov 2019 I bought 2 gig data as my data is disappearing from Telkom. the only thing they can advise me is to change my password on my router. now the default password is Admin and username: Admin which I did what they asked and it did not work. I then on Sunday went to the Vincent Park Branch in East London for them to assist and they said I should bring the router so they can have a look. I went back home and today went back there again with my router and to be told that there is no technician in today that can assist. This is unacceptable, You wait in a long que and then no one can assist and my data is disappearing even after 12am when I am sleeping and my phone is not connected. I also have an app that detects any new users so where is my data going