I have a similar problem, my wife wants a divorce and has threatned me with immigration because she wants money that I haven't got, on a non o that will expire in June, I don't want to want to go back to the UK and under 50, but if just I don't divorce her, that be ok? to stay till June?
It doesn't matter where the 400k comes from. My wife's mum put 400k in my bank for 2 months and I got a one year extension no questions asked and after I got the visa I transferred the money back to my mother in law and ive done 90 days reporting no issues whatsoever
I got out of paying a fine at phetchabun immigration before, I just told them I had been staying in Bangkok and refused to pay it but my wife did the talking