If you fire someone over your mistake like this, then you better never take advantage of the server forgetting to charge you for dessert or the cashier that miskeyed a discount on your purchase or someone who gave you extra change or whatever.

Human error happens. Unfortunately this time it was yours.

We’ve probably all had a weird paycheck at some point and thought “huh…oh well” and moved on with our lives. It’s not like your employee intentionally took money out of the register—you handed it to him.

Suck it up as the cost of doing business and be more diligent moving forward.