When a package is deemed undeliverable by the courier, the parcel will be redirected back to the original shipper. Common reasons for packages being marked return to sender are a typo in the address, listing a P.O. Box for a Next Day shipping order, inputting an incorrect zip code, or leaving off an apartment or suite number. Please contact customer service so that we can assist you with reshipping your package. Additional shipping fees may apply if your address needs to be corrected.