A friend recently bought a new prepaid phone with Telstra and is on the Encore prepaid plan, with a $30. She uses a mobile only very rarely, so I'm not sure that this would have been her best option, but that's beside the point.
Is there any legitimate reason why they'd be sending her a text after only a fortnight telling her her bonus calls and data had expired?
$30 doesn't get you much at all with Telstra, maybe she did use it all up.