We Found A MAGIC Fountain! (Writing Prompt)

It's a lazy afternoon on a blazingly hot Saturday, so you and your friends decide to go to a mall to cool off. Once you arrive, you notice a water fountain where people are tossing coins and making wishes.

You know it seems silly but you close your eyes, make a wish, and toss all the change in your pocket into the fountain.

It turns out the 23 cents is the precise amount needed for the wish to come true based on inflation. Everyone is throwing in single coins but the fountain requires exact change. As the coins float the bottom, the ground shakes and the water turns black. A slip of paper floats up to the top. It reads, "If you want to proceed with this wish, set the paper back in the water."
You crumple up the paper and drop it in.

As you walk away you realize you made an awful mistake and you can't take it back. There's a daily limit of one wish per person. Now you must undo this wish.

So, what was the wish?
What was the fatal flaw in this perfect wish?
What are the negative consequences and who will this affect?
What do you need to do to stop this wish from happening?

Now tell this story in first person from start to finish.