Caller: I don't know

Automated message, I don't get all the way through before hanging up but it starts with 'Dear customer, your debt of blah blah blah'. This is a different number for the same automated message I got a few days ago as well - they left a message of the pre-recorded message. That time the number was (07) 3301 9789. At neither time did they actually state the company I'm supposed to be in debt to!