My employment came about from the Aussie company i was employed with, they set-up a joint venture out here, i was confident the work permit would arrive.
My second work permit came about after my first contract was done, i holidayed here for 3 months before i was heading home, the two companies from the original joint venture separated with the Thai company buying out the Aussie one, they offered me another job, this second time round it still took a month or two to get the work permit sorted.
Ive just had my work permit extended by two years, even this took nearly a month for HR to sort out.
As to the OP, yeah fuck working for 5 months without pay or work permit, money aside the mere fact you was/is on a Non-O and they had not made arrangements to convert it to Non-B should have raised serious alarm bells.
Do you have any recourse, I doubt it, situation licks balls but unless your willing to engage a decent (expensive) lawyer i reckon your just gunna have to cop it on the chin.