@Jacques ************
OK so you got the Non B issued in country? If it was a year ago then you are no longer on a non B visa but an extension of stay based on being employed.
That extension finished the moment you finished your job. You are on overstay from that day.
Usually the way it works is that you get a letter from the employer stating that you will be finishing on xyz date which could be a week or so away. You take that to the ministry of labour and cancel your work permit and then immediately go to immigration with the documents from the MOL to cancel your extension and immigration will give you a stamp to stay until xyz date.
Whether you can still do this will be dependent on your employer. If not then the day you finished is the day the reason for allowing you to stay finished. You must either apply for an extension based on another valid reason, and meeting those requirements or leave. There is no grace period.