I had the same case like you. Your working permit is cancelled when you cancelled the Non B visa / extension. If you havent got your work permit before you got the job, you are on amnesty.
I got another job, but it was more than 15 days since I cancelled my WP so I fell to amnesty.
I have similar case, but I had single-entry non B visa, so I hadnt left the country since last year.
I resigned from my job last June to move to another company. However, my last working day was June 30, and my Non B extension was cancelled that day along with the work permit. I got another job offer last week, but since now I am on amnesty, the immigration office said I cant get new working permit.
Is the answer to stay past Sept 26th the same for me?