well I do my 90 day report and been here 12 years. Also i am. US Consulate Consulate Liaison and when i asked them.... they had no udea why they should be asked to certify my residence here in Kingdom. But hay.... who knows. Never had a problem with what i have always had getting driver's license.... tax folks.... etc.
As for a "certified letter from your embassy".... never heard that one before. As per their requirements is your passport, your visa, residency slip from Thai Immigration.
Funny that... Bangkok Bank is typically easy to open an account with. Remember that this is Thailand and as with everything else like this it depends on who, when, where, what day of the week it is and whether or not they had a bad breakfast. Try again... just wait a day
oh I went in. My embassy.... my country.... US territory. Made enough noise about it as a y good loudmouthed American would. But I did wait outside in thr waiting area our of ear shot.
You can go with her... to Citizen Service... but if for her interview... then they will not allow you to be present and will be asked to stay outside in waiting area out of ear shot so to speak or mayne even out of the building all together if the day is set aside for said interviews. Remember also that she will have to prove a reason why she will NOT stay in US.
Contact the Australian Embassy and the press the issue with them to take action. Sometimes being able to yell or at least be forceful as a 'foreigner' works. Australia has their version of the US FBI here in Thailand and these crimes are within their purview to investigate with the Thai authorities.