I use only one app on one mobil phone, but SCB cancelled admittance via www. When they stopped the internet admittance, so I don't understand why you say that they don't stopped the use of a PC to to do banking with them, but it looks that you did not use a PC for banking with SCB
The Danish Embassy of Denmark do make affidavit. But when the trouble started they changed from doing it from the tax return to now want pension letters from pension givers written in the English language and send to the embassy via the Danish E-letter system.
my experience are that if you send by Swift, then the Thai bank charges ca. THB 500 and it do not show on your banksystemet, you have to go to the bank and have them print out a copy of the transaktion.