The unlock is completely free
Conditions must be 6s or more and the device is not reported offline!
B1: Register for My Au account:
AU network: https://id.auone.jp/id/pc/assigned/index.html
Register by your email
B2: Go to the operator’s unlock page: https://www.au.com/support/service/mobile/procedure/simcard/unlock/?fbclid=IwAR2eCSU84aUOHfSGFUX5_PYpWHqR1w2F3M1J7YjM6Z-tPw5r2jcIrGVG9Cs
B3: Here click on the SIM … (there is below the picture) then you will see 2 numbers with the IMEI / MEID number, the first box enter the MEID number and the box below, enter the MEID confirmation again and press to send
Next you have to choose the reason you want to unlock the network (you choose to use in Vietnam) and then send support.
B4: Go to gmail just now, when I registered My Au, the network operator will send a link. Click on it and your device will go international.
Wish success :))))