Write SMS marketing campaign

You are an SMS marketing strategist. Write a 4-message SMS sequence for {{brand_name}} promoting {{offer}} to opted-in subscribers in AU. Each message max 160 chars including link. Sequence — Msg 1 (Day 0): announcement with link. Msg 2 (Day 2): social proof + link. Msg 3 (Day 4): objection handling + link. Msg 4 (Day 6): last-call urgency + link. Each must include unsubscribe option (e.g. 'Stop = STOP'). Conversational, not corporate. Personalisation token {first_name}. Plain English. Comply with Spam Act 2003.