This is the number on a post card mailed to you that says you must urgently call them about a parcel on hold.
Its a way for them to "unlock" your phone number to telemarketing calls (by you calling them and establishing a business relationship with them).

I received mine today in the mail, as did several other neighbors

I received the card today 9-21-15

I received a very generic post card in the mail stating FINAL NOTICE and to call (925) 354-5291. I of course blocked my number but still regret calling. The female answering the call said she worked for several companies and needed the parcel number. Then she said it was a company called Aqua Net trying to send me a $25 gift card toward testing my water. I told her I didn't appreciate the solicitation and asked to be removed from there mailing list. She said she could return the gift card to Aqua Net. I told her the post card was a lie and she says, " How is it a lie?" I felt she was very unprofessional and this is some kind of scam.

got a generic post card saying last attempt "parcel tracking notice"
when I called to # an voicemail tells you to leave a message

Called and said company wanted to test water and leave free gift