Tough spot bud. When it comes to money Thais are pretty aggressive, if it’s theirs or not theirs. Consider the save face ingrained culture.
Why can’t you pay? Do you have anything coming in soon? Any way you can pay them with time? Question why didn’t you tell them your dilemma ahead of time? You may have been able to work something out instead of leaving? Are you on the street now?
Contact the foreign tourist department , available to help and advise you.
tourist is 60 day with a 30 day extension, if so chosen! Overstay a day or two is a common mistake. You may or may not have to pay 500tb per day OS. As others say apologize and pay the fee if required. They will stamp your PP with OS on it.
You can also consider changing your flight. Although even if you have a flexible ticket it’s very expensive.
the insurance claims should be split up by the top four companies. Divided by four each month or three months. After all other administrative fees. Other companies could merge with the top four, or remain private for nationals.