Here's my perspective, for what it's worth. We only have so much time in a day. The vast majority of said time is hands-on shop work. Some time is allotted for communication. Within that time, I have to quickly skim through emails, texts, missed calls, etc. with an eye out for people related to the job(s) I'm actually working on in the shop. Those people are my current priority. Below those, if I have the time and inclination to chit-chat, I message back & forth with people who have pending orders that I am not actively working on yet. In any of these two types of communications I have to send pictures & give descriptions, explain which materials I like & why, listen to them tell me their thoughts, etc. Communicating can be an exhausting job in itself. Lowest on the line is new order requests. I read those less than any other & respond even less. It's not that I'm being a jerk or not appreciative of the interest. It's merely that I don't have that much time in my day to do all of that plus actually build a cue.
Here's the kicker. Every single person who reaches out to me feels exactly like the OP, like they matter above all else. They feel frustrated, almost offended if they don't get a response from me in the time they think they should. It doesn't occur to them that if I were to drop what I am doing to speak with them, that's time tacking on to an actual cue that somebody else is waiting on. While your selfish side might be ok with that, it's not so awesome when it's the other way around. And I'm just monkey in the middle, damned if I do & damned if I don't. I get *****ed at by all sides.
I wish it weren't like that. I wish I had an office with a secretary to keep up with all of it. I wish I had a shop manager who could lay out & direct the day's work so all I have to do is make cues. The world isn't like that, though. I have to do all of it on my own plus live a life outside of my shop. While I do honestly try my very best, I'm admittedly not great at it. What I am good at is making cues. And that's why people suffer me, and I sincerely appreciate their patience & understanding.
Sorry for the dump there but I imagine it parallels your situation. The case makers aren't a$$holes ignoring you. They're people trying to do the best they can to juggle work load with communication while hoping to not piss off too many people. Be patient and you'll get in touch with somebody, and you'll get the case of your dreams. The people you're reaching out to are apparently very busy for a reason, and to their credit they are prioritizing the work they currently have over your idea. When it's your case they're working on, they'll ignore other potential buyers while they focus on taking care of you.