Mailed a package to the wrong buyer

[njsmirk]

While printing a shipping label on a recent sale , I had to reprint it because of a printer malfunction Later I realized that what I had reprinted was a labelprevious sale sold 2 months ago. Since the items were simular I did not notice anything paculiar until later . I  attached that label to a package intended for a different customer and mailed it.

Same day, I contacted the USPS to see if they could intercept the package But ....no they said they could not.

Now what?