[Resolved] Sony Ericsson Z550i — SIM cards outside Australia cannot be used!
We bought a mobile phone Sony Ericsson model Z550i from Vodafone shop in Australia complete with prepaid sim card, and it worked well in the country. But when we travelled to Indonesia and Malaysia, we tried to purchase/replace sim card there but Z550i did not accept it. Luckily we had another mobile phone (also purchased in Australia), an old Panasonic, that accepted sim cards from Indonesia and Malaysia! Complaint to Sony Ericsson in Australia had NO response. My advice is DO NOT buy Sony Ericsson Z550i (or other models, check it first) when you intend to travel outside the country!
Complaint marked as Resolved Aug 13, 2020