Hi @jzheng16 ,   Welcome to the community!   We're sad to know that you're having issue with your mobile service. We're able to locate your account and ran an initail test to the service. The result shows no network issue we'd like to confirm what troubleshooting have you done so far.   Please do the following troubleshooting below. ( Skip step if done) Power cycle the handset. After turning off the handset, battery should be removed. Put it back after at least 10 seconds, then turn on the handset. For handsets like iPhone or any handsets which don't have a removable battery, restart must be done. Complete a manual network selection  Select another network, then select Vodafone/Optus/Roaming and then turn the phone off and on again. Change Network Mode/Preferred Network (from 4G to 3G or vice versa). Do isolation test Try different SIM card or Handset Let us know how it will go.   Cheers! ... View more