Douchebags and My Mail

Today I encountered a dilemma I've never expected to encounter. It has infuriated me to such an extent that I am seriously on the verge of committing a serious crime.

A few weeks ago I ordered a handmade dress to wear for rehearsal dinner for the wedding. It was cheaper than almost anything that can be bought, it had the cutest fabric, and was going to actually fit my body. I was so excited about this dress. It got shipped last week. Somehow, the seamstress of said item only had my old address, and shipped it to such through the post office. I had all my mail forwarded by the post office about 3 months ago. Today, I couldn't stand it any longer and contacted the seamstress to find out where my dress was. She said she had delivery confirmation from May 30. Then informed me it was at the old address. I took a quick drive over there and knocked on the door. No answer. I rang the doorbell. No answer. I could clearly see the guy's car and could hear him moving around, but he was not answering the door. Pissed. I call the landlord and let them know the situation.
As I'm pulling out of the parking lot, I see him come outside, only wearing his underwear. I said the boy to talk to him and he claims he's never seen any packages for us. He goes in. I make the boy knock on the neighbor's door to see if this is true. Neighbor informs us he has seen a few packages for us and assumed they got passed on to us. This is the first we've heard of it. He knocks on the guy's door and he then tells us that "oh yeah, I got a package and it only had a crapload of coupons in it." So not only did you keep a box of ours and not tell anyone, but you OPENED IT?!?!?! WTF?!??!?!?!?!?!?!
At this point, livid is an understatement. We hightail it home and I call the police, who direct me to the prosecutor's office. Complaint filed. I called the post office and I'm meeting with them tomorrow, as the package should have been forwarded. Besides the point in the scheme of things.

WHAT IN GOD'S NAME GIVES YOU THE RIGHT TO OPEN AND KEEP SOMEONE ELSE'S PACKAGES AND/OR MAIL???? WHO DO YOU THINK YOU ARE??? YOU HAVE OFFICIALLY PISSED OFF SOMEONE WHO CAN NOW MAKE YOUR LIFE HELL AND I HOPE YOU UNDERSTAND THAT, BECAUSE THE WORST IS YET TO COME.