What should I do if my work permit has expired in Thailand and my company is unhelpful?

okay, the work permit is in YOUR name, that means YOU are responsible for canceling it.

Also your extension is in YOUR passport meaning you are also responsible for that.

When you stop working you CANNOT just stay on your extension until it runs out :/ You need to go cancel your work permit then go cancel the extension then leave the country and get a new visa or re-enter on a visa exempt entry.

You currently are on overstay from the date your work permit canceled. I doubt you could stamp out at a border without having canceled your extension at the immigration office first (and clearing the overstay fine you will get).

You need to get the receipt of your work permit being canceled from your old employer, take that your termination paperwork to the immigration office, cancel this current extension, pay the overstay fine, and then you can leave the country.

Good Luck (y)

You are on overstay, and possibly other than a large fine, big trouble if you get caught.

Sorry to be blunt but from experience, it sounds like your company could not give a shit, because they could easily sort out the WP for you. Time to move on I would say. I presume you are still working for them. So just say good bye. You will need to cancel your extension of stay of course. Or just go work in a different country, like Vietnam for example. More money and lower cost of living too.

Do you have an extension of stay? Since you say 4 months left I guess that is the case.

Then you have to cancel that and leave the country.

Your company sounds like very unserious but even though its your responsibility to know the due date of your work permit and you shouldnt have kept working after wp expired.