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.
This doesn't apply to Claire as she will be online at one point. The whole crackdown of Ed Visa was because people didn't go to class and used an agent to do their 90 days report so they never had to show up to get tested.
As long as your Thai improve a lot every 3 months (90 days) when you get tested by officer, you should be fine. The time of not going to class on ED Visa is over. They are very strict on not getting ED Visa for the practically of it.
You need an agent to hold your hand to immigration, right? But you don't tell us where you are located: BKK, CM, Krabi, KK, and so on. How do you expect anyone to help you or have recommendations without knowing where you are.
The hic is that your USD need to be in pristine condition or would be rejected. The best way is to go to a bank on your way to the border and get some USD. At the border, they do not push to be paid in USD because they make a fat cut with everyone who pay in Baht or Kip. Most countries the visa is around $30 (1k baht), but they will charge 1.2-1.3k baht if you pay in Baht.