Real Life Mystery

I got this package in the mail in March. There was no return sender and its contents were highly perplexing. First of all, my last name was spelled wrong, and out of all the mis-spellings I have seen of my name, this one was the most original: Rubinstein was spelled: Rubinsstein. Two S's?? Come on now! There was also no black lines over the stamp indicating that the package had even actually been mailed...but my mailbox can only be opened with a key, so if it hadn't been mailed, how did the sender manage to get it into my mailbox? Even more bizarre is the little pink note inside. The handwriting is unfamiliar. The note closes with a friendly: "Love Mom & Dad" yet, my parents have been divorced for ages! My roommate ate the cookies and sweets and has yet to die as a result, so the sender obviously did not intend to poison me. I have yet to solve this real life mystery...who is the sender??