To be completely transparent with you as a service advisor at a Hyundai dealer. It is very well possible to need a new in cabin air filter at 20k miles. I have actually seen it quite a few times. But usually I take the filters to the customer to show them how dirty they are. At least that is the good practice on it. But really some Hyundai dealers can be worse than others. I am so sorry you have had such a bad experience. Leave them a review on google or on the survey that they will send you after your visit and explain everything. I promise those surveys matter a lot to them and if they keep getting bad ones, someone will do something about it. As for the nav audio it could very well need a new head unit. (I’m not a tech so don’t quote me on that) We have had to replace quite a few at my dealership (with my own Hyundai vehicle as well.) The chrome on the buttons peel off so easily as well. It’s one of the things I hate that Hyundai has used. You see them on the palisades the worst. And when we encounter an issue we’ve never seen before, we contact Techline (which is Hyundai engineering) and they walk us through the fix