take your termination paperwork to the immigration office where you got your extension inked in and see if you can cancel it, most offices let you do it a few weeks before the actual termination date on the paperwork and they stamp you in until that date (so you don't have to leave the day you cancel it)
BUT
Some offices make you cancel it effective that day and then you have to buy that 7 day emergency stamp to get out of thailand in a week.
You may or many not be required to show your work permit is cancelled, that's totally up to your immigration office
listen it's not the work permit cancelling that is gonna mess you up when you come back in and try to get the Non-B visa at the immigration office,
It's you not cancelling the extension of stay that's in your passport BEFORE you leave the country <- that's what lets you stay here and just stamping out isn't gonna cancel it officially at the immigration office,
so you need to get that cancelled BEFORE you try to bounce out/back or you're gonna get fined when you go to get the Non-B and extension with the new employer
Sadly there's no way to tell why they're rejecting your 90 day online application
you haven't gotten a new extension since the last 90 day report have you? if you use previous data, that field auto-fills and if you got a new extension you need to change the year
ALL visas to thailand are now online eVisa thru the web-portal
so what that means is
IF in fact you really have to go get a REAL tourist visa you need to go to a nearby country whose consulate you're going to apply for the visa thru, log into the system, fill out the data, upload your documents, pay, then wait for the visa to be emailed to you in a PDF file that you print and present with your passport when you stamp in
However with that being said
I think it is far more likely that your new employer really just wants you to cancel your current extension of stay (at the immigration office that issued it) then exit/re-enter the country to get a 60 day free stamp (visa exempt) entry stamp <- you can apply for an in country Non-B visa from a free stamp entry no problem at all
CHECK with the new employer again and ask if you can enter 'visa exempt' on the 60 day entry program.
If so you can cancel your current extension (which you need to do anyway) then use a service provider in your area that goes to the border and back to get you stamped out/back in on a 60 day visa exempt entry
You might wanna re-think that "didn't want to print anything out" mindset.
That PDF the consulate emailed you IS your visa for the next 5 years.
And
all it's gonna take is an officer at passport control not paying attention and you'll get "bad stamped" <- stamped in on a free stamp entry rather than your 180 day DTV entry
Takes a second to print it fold it up and put it in your passport. Well worth it because you get bad stamped and it's on YOU to get the stamp corrected š
while you can apply for an extension right up until the day your 90 day stamp runs out I sure wouldn't cut it that close, because if you don't get all the documents etc correct and you're on the last day you can run yourself out of time. š® Best of luck with it ...
Nope, if they take your money (the 1900baht) and give you a receipt with a return date you'll get approved. They won't even let you apply if you're not gonna get the extension