Go to your SIM card shop and ask them about the “for the bank” certificate—they’ll know what you mean. They will give you a certificate (there’s no fee at DTAC, but I’m not sure about other SIM card shops). This certificate is a requirement for your SCB account (usually SCB is the one affected by this) or possibly other banks. Then, go to your bank and submit the certificate from the SIM shop along with your passport and passbook.