Caller: Claim to be from Telstra

You receive a recorded message saying this is Telstra and your internet connection will be disconnected in 24 hours, press 1 to talk to a technician. if you press 1 you get an person with a strong Asian accent that reiterates that my internet will be disconnected. I have received this call twice today alone and many times over the last 6 months - obviously a scam
when to try to return the number - the message is the number doesn't exist