Am I Overstayed If My Work Permit Is Canceled After My Employment Ends?

Hello all. Clarification and help please.

I have a work permit + extension of stay (both valid until Aug 2020).

My hotel closed and my employment will be terminated, last day on April 30.

Our HR said they have 15 days to cancel my WP and they wish to do that on May 15th as a 'consideration' for me to stay longer because of the current situation.

My question, if they cancel my WP on 15th May (and of course I have to cancel my extension of stay on the same day), am I already overstayed because my last day of work is April 30?

When is the best time I shall do the cancellation of WP and extension of stay?

Thanks much!