That's awful, I'm so sorry this has happened to you
Has your partner been online at the Arena since then and read your messages too ?
Have you tried to contact them via Facebook or by email (if you have their email address. sometimes these things are in the persons profile)?
Maybe try posting a thread in here with the title as "trying to contact ---- (persons arena name) and see if they respond to that. Even if they don't, someone else who knows them or who knows how to contact them might reply
If you've tried all of that unfortunately with swaps/trades there isn't much else you can do except for leaving them appropriate feedback to warn the community. If the person has a genuine reason for not sending your parcel yet and they sort out the problem, then you can always change the feedback later to reflect that.
I hope that your swap partner does respond soon