Until recently, I could depend on the mail I put in my box for pick-up to be faithfully taken to the post office and delivered to the intended recipients (and they were). However, 3 checks haven't made it to their destination, which means I will most likely have to put out money twice for each bill. Why doesn't the post office RETURN TO SENDER if the mail is deemed deliverable? i always put a return address on all pieces of mail.