Upon reading the thread at HardForum, it hasn't been long enough to begin taking these measures. Appears only to have been 10 business days. Once had a piece of mail (containing a money order) take over four weeks (from Indiana to Nyc) before I received it. Was postmarked on the precise day the trader had sent it - just lost in the shuffle at a post office somewhere. It unfortunately happens.
Fortunately in my situation, the specific trader and I kept up good communication. We eventually resorted to PayPal, and he began the claim process through the postal system. The money order arrived a few days later. Would have a bit more patience, and attempt to reach the trader through the channels you've had success with prior to prematurely jumping to a conclusion.