Thank you all for your feedback. It is amazing that an airline (or any business for that matter) would add a feature like this without making sure that it properly works. All it does is upset your customers when it doesn't work, most of whom would have been perfectly fine if the option didn't exist in the first place.
I have never flown business or any other class on Jet before. Besides 'Book your meal' not working, how are the food and drinks in business?