We've often suggested simply hanging up as the best way to deal with dodgy telemarketers. That strategy has just got some serious backing, with the ACCC and ACMA joining forces to recommend hanging up whenever you suspect something dodgy on the other end of the line.
The advice from the two regulators particularly applies to phone scams, where callers attempt to grab personal details for fraudulent purposes. The advice can be summed up simply in one sentence:
If you get a cold call from someone claiming you are entitled to a refund, have won a holiday or have a virus on your computer, hang up immediately.
That said, it's even simpler to hang up whenever you receive an unsolicited call. Being tolerant is frequently a good idea when you need to contact a call centre yourself, but in the case of outbound calls you didn't initiate, showing no mercy is a prudent policy.