This reminds me of a small order (relative to this one for sure) that I bought some time back.
General lack of communication, had to remind him several times what exact parts I ordered, follow up as I knew a couple pieces were being drop shipped, , etc., etc. Of course my credit card was charged within hours of placing the order.
I knew SEMA was around the corner and I'm sure that didn't help and I think I was pretty patient (several months). Parts got here eventually and all was good, but I've never ordered again because I just didn't feel like he cared or just had too much ego to say sorry it took a while and SEMA is making me crazy.
I think *some* of the problem is these business owners are running around trying to do everything, run the shop, manage the business, employees, projects, shows, keep up with the forums, and on and on, and then they run a parts business too. Ego tells them they can do it all and that's how they built their business and success. Awesome. But...
At some point they can't remember or have the time to do it all and suddenly everything is falling through the cracks and more often than not - ego prevents them from accepting this or apologizing when it does happen and everybody loses. Customer gets pissed off, vendor is frustrated, future business lost, and the rollercoaster ride takes off.
I think (no real "build" experience) here that the profit in the shops is in labor and service - not in mostly small profit margins from selling parts (even though it certainly feels like that on my credit card

) and it's easy for the "admin" work of ordering, tracking, shipping, customer service, to take a back seat.
In these cases, a key to further business growth is finding someone they can trust to take on responsibilities like keeping track of these damn orders, keeping customers apprised of statuses or delays, and much of the other behind the scenes stuff. Tough order to fill in some cases as I'd guess most of us want or expect to talk to the owner. Their the ones with the experience in fitting all these off the wall combo's we end up with, right?
Then there's the stuff I bought from Autoloc at a Good Guys event - what a HUGE mistake that was. Lesson learned there. That guy bleeds shyster.
Hopefully this gets resolved quickly from here on out. Good luck.