When i applied in May they said 14 working days and it was right about that time. If you had to provide more documents I would count 14 working days from the day you provided the requested documents. You can email them if its been longer. Start researching your options in case approval doesn't come in time.
to be honest, that one bank has been the only problem I've encountered so far in Thailand. It just happens to be a major problem. Very surprised the government or lawyers haven't done something. But I don't pretend to know Thai law. Just seems almost criminal whats been done to some account holders
im in a similar situation. Gave them all required info 2 months ago, but still frozen. Did my extension end of July so waiting until my 3 months is up before I go into the bank again to try and get final resolution. Hoping if they will not unfreeze that I can at least put 400k in my other bank so I can close the Bangkok account. Absolutely no reason people trying to do the right thing should have been treated so poorly. Hope you get your situation solved.