never carry the passport with you outside! (unless you have to go to immigration). Nowadays one hs a photo of it on the phone you can show for any occasions. Of you don‘t have a phone then just carry a paper copy with you
well then its on them to go after and find the reason for the rejection they have the ressources and contacts needed. Just keep on asking, you have the right to know
I think you therefore need the approval from the landlord if you want to do it yourself, would be easier to let it have done by the landlord who did it the first time.
well I don‘t know from where you got your information that only $ 10k is allowed to bring into Thailand and above has to be declared? I still rely on this piece of information:
are you sure it has to be in baht or isn‘t it enough you carry equivalent amount in any foreign currency? We never brought any baht with us and changed first time after arrival