I had a similar experience today when I visited a local branch. From what I understood, the information will eventually be sent to the email address mentioned in their message. It doesn’t matter whether you visit the branch or not.
I ended up calling customer support, and they confirmed they would either send it to the email for you or let you handle it yourself. I’m not sure if the process varies at other branches.
He explained to me. For non-U.S. citizens: If you don’t have a Thai tax ID and no income is listed on page two, you’ll need to check "Yes" and provide your home country’s tax ID. It seems they require at least one tax ID. I told my case that I'm longer then 180 days in Thailand, no taxable income, not working, no work permit, and not registered anymore in my home country. I said as well that i didn't get a tax id in Thailand in the first place.