dude, if i were you i'd be putting things on ice for a bit and reinventing my postal strategy, completely. new drop, new look, new qa.
as for methods i can tell you with others i've had a number or tracked but only one non-tracked not arrive, i did get the partial resend through from them though. i'm not saying i won't try it again some time but hesitant to do so. this stops me with some options but so be it. i can see it is an additional complication.