Hi, Sleiman,
I'm very sorry to read about your issue.
Telstra support staff strive to provide the best possible service to customers, and I'm disappointed to read that your interaction left you displeased.
Please feel fee to submit a formal complaint via THIS form should you wish.
All interactions are logged and stamped with the employee's ID, so the person which provided you with poor service can easily be identified, and the interaction will be investigated thoroughly before appropriate action is taken.
I hope your faith in Telstra will be restored.