This is over the top nit-picking BS from CW. In the numerous years I had to deal with them...always found the entire experience dreadful. Baditude, ignorance, resentment and disdain in abundance.
As for Bangkok Bank, they need to seriously update their IT. A 12-month or even longer statement should be printed out in a matter of minutes at any branch. Their networking is horrendous. I have banked there for 22 years and overall mostly satisfied. But when it comes to something as simple as a 12-month statement, they are so far behind. There are other shortcomings, but will leave those for another thread.
I hope you get it sorted out, but am highly doubtful that the email print out will suffice. Hoping it does and if so, will be pleasantly surprised...but not at all optimistic. Keep us posted.