Tech support scammer tries to scam me out of $299

I called these scammers on the Aussie number that appears on their fake popup: +61 1800431247 which is a VoIP number provided by symbionetworks.com and they refuse to take down the scammers VoIP number. The scammers sometimes seem to be playing a message saying "number is not in service" if you dial from a silent number, so you may have to display a number (probably Aussie number) to get through. The scammers also sometimes end the call after a few minutes and call back from +1 562-684-4972 or +1 888-308-4925 or +1 888-727-1224 to check that you aren't spoofing a number.