Hi @kyuhyunchoi
Since you are already out of the country and no longer need the TPG SIM, please fill up our Confirm Identity form with your request.
You'll need to select 'confirm identity' as the contact reason and leave a short note in the comments section that you're looking to cancel the service. We also recommend popping your overseas number into the contact number option, including any area codes, so that we can reach you by text.
BasilDV
