@Thelittle ***********
I’m not denying you have the stamp (you showed it earlier in this thread!). I understand the predicament you are facing, and I can only suggest you go to the office and get your passport back. It sounds like you are now on Overstay, so will be fined when you leave thailand, and will be flagged if/when you try to re-enter you will probably get interviewed.
You could fly out to Cambodia (or somewhere close), and then try to return as a tourist. If you’re going to do that, I’d advise re-entry via Phuket or Chiang Mai if possible. If you try Suvarnabhumi airport you will be questioned!
I’m telling you this as I was on an Ed.Visa but had to leave for personal reasons. I came back into suvarnabhumi airport a few weeks later and was interviewed for 1 hour before they let me in!