If you have a large position relative to the daily volume, I got out of a situation like that by having my broker put in a "not held" order (their suggestion).
They take the entire order you want to sell, but they somehow don't show the quantity for the ask. My sell got posted in A/H. I'm not sure how they did it, but they did. It may be worth an inquiry. The stock I sold dropped another 5% the next day after trading flat all day long the day I sold in a bad market.