a teacher at my school claims that his old school cancelled his work permit by phone. the teacher still has the physical work permit, which states that it and the non-b visa are valid till the end of the month, but his former school claims that his work permit was cancelled on the 12th of this month and that he has overstayed his visa.Can a Thai employer cancel a work permit by phone if they don't have the physical work permit?How can one check to see if one's work permit has been cancelled?

Current regulations seem to allow non return of work permit in at least some locations so that sounds possible but employer must provide a letter to employee addressed to immigration in order for the person to cancel his extension of stay. If employment has ended, regardless of work permit, the extension of stay ended on the same day.