I called back number (02) 1257 8681 rang 2 times then goes to busy tone.

pest call so just didnt hang up for about 2 hours to give them one less line to irritate people.

Dodgy Indian call centre claiming to be from Telsta

Getting a lot of calls from people who struggle with the english language telling me that my computer has a virus ? the phone number they use seems to change each day and when I ring the number back I'm told the number is either wrong or incomplete.
yesterdays number was (02) 3245 6131