The replacement of the modem/router is subject for approval and investigation, once its approved the tracking details will be sent via Email or SMS.
Metro deliveries to capital cities are normally made on the next working day. Deliveries in other areas are normally made within 2-7 working days, depending on your location.
For more details you may check this article, How To Check TPG Modem Delivery Status.
For the faulty modem/router you may return it by post to 65 Waterloo Road, North Ryde NSW 2113. Ensure to quote your username or customer ID as a reference and include a brief reason why the modem should be returned.
Let us know should you require further assistance.
I recently requested a replacement modem and what is the progess of receiving the modem and return the faulty modem?