In your example you bought 50 shares of a stock. What price you bought them at makes no difference and has no effect on what you will get when the stock delists. If the stock delists at $100 because it is a movie stock and the movie made $100 million at the time of delist, then you will be paid H$100/share. 100 * 50 = 5,000.
Now, say the day before the stock delists it is currently priced at H$200/share. That would give your 50 share investment a H$10,000 value. If you sold your 50 shares at that time you would get H$10,000 minus the commission. In this case commission would be 1%, so you'd receive H$9,900. (Delisting stocks have no commission.)
Delisting a stock cashes out ALL shares, whether held long or short. In effect a delist is a forced Sell/Cover order with no commission.
As for why you wouldn't sell your H$200/share stock if you KNEW it was going to delist the next day/week/whenever at H$100/share, well, you probably wouldn't. But as Antibody is fond of saying, "No one knows anything."