That is AWESOME.
I was thinking about chiming in earlier with respect to the value of doing things yourself instead of relying on manufacturers warranties… However, I think the OP has learned a very valuable lesson and skill. Now he’s not afraid to repair a loco himself, saving frustration, time, and money.
I tear apart and rebuild every single loco I purchase. I do this in part to install DCC but also to learn how they work. Every one of my steam locos (to include the N scale version of the Spectrum 2-8-0) has been gutted down to the bear wheels and reassembled in order to tune and unbind the valve gear. My point is that once you open these things up your realize they’re not mysterious black boxes but relatively simple machines that you can repair, oft times using parts from your parts bin or the electronics store. Worst case scenario is what the OP went through, i.e., ordering special screws. But now he has a bin full of these screws he can use for the next problem.
I understand the principle of holding manufacturers accountable for their work and for their warranties. However, doing so can often be far more work than just correcting the problem yourself. I’ve found I get a lot more fun and miles out of my trains since I take care of all repairs myself.