DanielHerbert77 - Your user profile page, your for sale threads, and trader feedback all show signs of buyers wanting to know where their stuff is, or wanting a refund, and not hearing back from you. I just poked around a little bit and arrived at my own conclusion based on the available information. If you are concerned about your online reputation, communicate with these people rather than shut them off and cross your fingers hoping the post office suddenly comes through. Everything you are selling and supposedly shipping should have been insured, so you should not be out any money after completing USPS lost mail claims. Did you ever contact your Postmaster? It's amazing how quickly issues can be resolved after speaking to your local Postmaster.
Maybe a disgruntled postal worker hates you and continuously steals your packages... Who knows... But you needed to let your buyers know what is going on.