There are several reasons why this would happen:
1. You were not at home at the time of delivery
Ararat Box stamps your phone number on the box and some post offices will give you a call to let you know you have a parcel in the post office. Others will hold it for 3,7 or 14 days. However some post offices may decide to ship the box back without giving you a warning. In this case you can contact them for further details and file a claim.
2. The address you have indicated was not recognized by the post office
If your address is incorrect then the post office will send the parcel back to Ararat Box. Some post offices in several countries can contact you via the phone number provided on the box in order to ask you to clarify what your address is.
3. The address you have indicated is correct but the customs office could not deliver the box
Rarely, but it happens that the customs office of your country holds the box and does not ship it to the local post office, it gets stuck there for a file and gets shipped back to Ararat Box.