This has happened to me in the past week, albeit RM was the courier in question and it wasn't stolen (though for all I know it has been by now since it was shown just stuffed/wedged halfway through the letterbox), just delivered to a completely different door/address despite me getting 2 emails (one from RM, the other from eBay) proclaiming it had been delivered.
Bought a new/sealed game for my Nintendo Switch (was between £45-£50 including shipping, so it wasn't dirt-cheap) and I always stay in the house when expecting deliveries. It wasn't the only package off eBay I was expecting on the day of delivery (the rest of which did arrive) plus I haven't been feeling 100% (bad cold) this week, thus it didn't immediately register that I hadn't received it until yesterday (3 days after the supposed drop-off date) when I went to play it and couldn't find it in the game pile. A momentary flash of panic that I had somehow thrown it out with the packaging later, I realized that something had gone wrong on RM's end and that I hadn't received it at all. I ruled out a errenous delivery to a neighbour pretty quickly, as if it had been delivered to one of our neighbours, I strongly suspect they would've knocked on the door with it that afternoon/evening or slid it through our box, as has happened before.
Sure enough, when I checked the tracking number on their site, the proof of delivery photo was of a totally different door/address in what appeared to be a completely different building - the tiles on the floor and the colour of the door were a dead giveaway; the 'close' in my building doesn't have blue doors for one. Besides which, we have a outdoor porch and front garden). This despite RM delivering at least two other packages to my front door that morning. Barring a tracking error being the cause (the cynic in me doubts that), this one is a classic, but hardly a surprising one given RM's determination to race to the bottom and beyond. I would've been annoyed, but by and large understanding if the package was taken back to the local sorting office and sent out again the following day if it was unable to be delivered on the promised date as has happened before, but nope, that's clearly asking too much of RM in it's current state.
Instead, an overworked & underpaid postie shoves it through a totally different door in a completely different building to meet a borderline impossible delivery quota, leaving me frustrated, without a game and out of pocket and a excellent seller on eBay in the lurch, but I got what I paid for I suppose. Have fired off a 'Item Not Received' complaint on eBay requesting a refund in light of all this, but seeing as this is a Bank Holiday in addition to it being a Sunday, I doubt I'll hear anything back before Tuesday and when I do, the fact that it was marked as delivered on the system, not helped by me not flagging the shipping error for nearly 3 days, will likely result in it not going anywhere with the refund request being refused. Just as well there were other copies of the game available on eBay and in anticipation of the complaint going nowhere, I have bought another, slightly more expensive copy of the same game and just have to cross everything that this doesn't happen again to it or with any of the other packages I'm expecting in the coming days. Not something I wanted to do, but all it takes is one screw-up of this nature for one to lose all faith and trust in a broken system that had somehow not backfired in my face like this until now.