Negative verb for "it will pay off" [closed]
It will haunt us (or come back to haunt us) in the future.
dictionary.com:
- to disturb or distress; cause to have anxiety; trouble; worry: His youthful escapades came back to haunt him.
You can use the phrase "come back to bite us". You don't even need "in the future", then, because that is implied.
The meaning of the phrase is that something that has happened or will happen, is or will be a problem in the future. (See this definition in The Free Dictionary).
For your example:
If we don't solve this problem now, it will come back to bite us.
In a more literal example:
If we don't kill this rabid dog now, it will come back to bite us.