I had a similar problem with my local dealer - they had trained technicians that could work on my PHEV Niro, but they had untrained people answering the phone who told me (on two separate occasions) that I needed to take my car elsewhere for service, because they weren't qualified to work on it.
It turned out that the people answering the phone were confused: they thought a plug-in hybrid or PHEV was the new all-electric EV car that Kia announced earlier this year, but still doesn't seem to be selling very much (if at all) in North America. I had to explain to them that a PHEV was a hybrid, like an HEV, only with a bigger battery. Once they understood that, the guy on the phone said "Oh... we can work on that one".
I only figured out that the problem was with the people answering the phone after I posted a somewhat critical review on Google reviews for my local dealership. I questioned how a dealership could sell cars that they weren't prepared to service. The dealership's PR
manager promptly posted a reply advising that I was mistaken, and they certainly were prepared to work on all cars that they sold as new cars, and that encouraged me to be a bit more insistent when dealing with the folks that answered the phone. This is one of the reasons why I suggested that you might want to say something in a more highly visible social media venue than this forum might be, as a way to get your selling dealer and Kia Corporate to maybe reevaluate their response to you.
If you haven't already done so, you might want to reach out to the shop that did the work and explain the situation, and ask them if they have any additional supporting evidence that they could provide to support your claim. It would be great if they still had the stripped bolt, but don't count on that. Still, they might have something.
I am inclined to believe your local dealer's comment that "the final alignment is done at the factory and not by the selling dealers". I'm not an expert on this, but I'd be surprised if dealers were expected to do alignments on all the new cars on their lots.
If I was dealing with this headache, one of the things that I would probably do is ask to speak with the district manager who you were told made the decision to deny the claim. The story about your situation was probably described in somewhat different terms by the time it made its way to that person. Sometimes situations arise that feel very unjust, not because of unjust policies, but because of imperfect communication. I once headed off a lawsuit by walking into my lawyer's office and insisting that he temporarily put aside all the legal blathering and letter-writing and court filing and just pick up the phone and call the opposing lawyer. Once those people started talking to each other, it only took five minutes for them to recognize that there had been a misunderstanding, miscommunication, and everything was quickly sorted out after that. It seems like there's a chance that you might be able to find a similar outcome if you can just find a way to get in touch with the right people.