@Daniel ********************
Anecdotally, there seems to be a consensus that older accounts (4+ years?) are less likely to be frozen.
That's been the case for me - 5 year old account, opened with the assistance of an agent. Still open and active, no issues.
Do you have the Bangkok Bank ap on your phone? You could try opening it to look for any messages about your account status. You could also try to make a small purchase, like topping up your Thai mobile phone.
However, I would only do this with a VPN active, with location set to Thailand.