You don't know if the school use an agent or not. You don't even step foot there, you have no idea what they do. Are you even fluent? Or you speak a few words? The time of abusing Ed Visa system is over, that's my main point. That's why I ask about your Thai skill.
The facts don't care about how you feel. The facts are that Ed Visa are heavily crackdown due to people not going to class. Therefore, once leaving the country, they can't go back to Thailand. They need to hire an agent to bribe officers just to get a chance to come back in.
As I said, the time of getting Ed Visa and not learning Thai is over, same with getting volunteer visa without volunteering. Both are heavily crackdown.
So if you used any kind of third party to get your ed visa (fixer, agent), and didn't walk yourself to school to fill the paperwork, most likely you were getting protected to avoid scrutiny.