Workaround?
At least login through the website should still work?
(for me it does but no joint account, try it!)
A bit inconvenient on the mobile but zoom in and you know the money is still there, transcations taken place etc.
To do "new" transactions there will of course be OTP sent to the one and only phone number.
I am waiting that they finally introduce an alternative two factor authorization without relying on SMS/Thai telephone number. Antiquated.