Caller: Scammer trying to access my computer

Indian accent, called saying she was from Telstra and that someone was trying to hack into my network and if i give her access to my computer she will show me how to stop it. When i asked for a number to call back on she asked me why i had to call back and got frustrated that i wouldnt just take her word for it. She refused to give me a number to call back on and said if I call Telstra they wont be able to help me