Please do not listen to angry old fart who have never used an agent in their life. They talk loudly, yet have zero experience so they can't provide accurate advice.
She will likely be denied entry, especially on a renewed ed visa.
She has two options:
1) Contact TVC (
@THAI *****************************
). They are the owner of this group. If they can't guaranteed your friend entrance, no other agent can.
2) If TVC can't, your friend has to enter by land using a facilitator at the border. Again, too risky to come back in by herself without help. Many agents offer border run still with guarantreed entry so just have to find one that help from the other side.
Please note that the fact that she speaks Thai is a big positive. There is 0% chance she get in by herself at the airport without speaking Thai. With her speaking Thai, and with the school principal on the phone with IO at the airport, I give her 50% to get in without agent. This is still way too low. I give her maybe 75% by herself at a land border. But with agent, it's 100%, and I would not risk it for 50-75% odds.