One word for a reward that will not be given [closed]

I think that the carrot and stick metaphor illustrates the point you want to make:

The phrase "carrot and stick" is a metaphor for the use of a combination of reward and punishment to induce a desired behavior.

Thus, the metaphor can serve as a visualization of what can sometimes happen in corporate and other settings, with executives "dangling" a promotion, for example (the "carrot") in front of the rank and file in order to get massive amounts of work out of them in exchange for very little reward.

In general usage, any promised reward that is really a tease may be referred to as a "dangling carrot."

(Wikipedia)