I got an letter from my the boss from my rescue organisation. And it is only 20 to the border. If still can not I pay an agent and I can go back. The agent told me this letter should be okay.
The problem was my rescue ID card was expired. So the letter is about that.
The boss from the rescue organisation in bangkok did called to the immigration they told me this:
I've already spoken with an official. They informed me that you don't have a visa and your Rescue Association card has expired. They don't have any supporting documents, so they need to send you back to your country. If you wish to return to Thailand, the foundation in Buriram Province must issue a valid certification document before you can return.
And yes afther the rejection my rescue did write this document for me. So let's try again at the border by land tomorrow.
first time I entered Laos (before my rejection) they asked me howmuch money I have with me I said around 5k baht. They told me you should have 10k baht with you for laos immigration. So I did go to the ATM. And check in again. But they didn't check it. Laos immigration also didn't check anything. (No cash, no return ticket, no hotel booking). Also not when I entered the second time.