@Jake ******
50k is a normal market price for an agency providing full service when you have nothing prepared yourself. This is considered freelance remote work combined with a Soft Power Program, although for some Western applicants doing it their own way, it may seem unusual. ( But this is an offer for only Norwegians, Swedes, Danes, All Arabian countries, Chinese, Kazakhstan, Russians, Ukrainians, and etc )
The rejection was not because of the 6- or 12-month course duration. A legitimate Soft Power course must follow specific standards, with a fixed total of 180 hours up and a fully structured program.
The instant rejection happened because the bank statement was not originally yours, and the transactions did not match the proof of funds provided. That immediately raised concerns about f a k e documents.
This is also why the agency advised you not to reapply right away. Hanoi Thai Embassy likely flagged the application for fraudulent documentation, and in these situations, applicants can even face bans. Any immediate reapplication is highly likely to be rejected instantly without proper review.
My advice is to first place the full 500k THB into your own bank account for 3 months, enroll in a legitimate Soft Power program, and then apply again through a personal interview in Laos or Taiwan.