When you start branching out and your art starts to sell, you will encounter many kinds of clients who like your art and want it for whatever project they are working on. Store buyers, magazine editors, interior designers, art consultants are all examples of people you may deal with during your day. One thing they all have in common is they are trying to please their clients or bosses and whatever YOU have will make their work life better. They will pour on the sugar to get what they want, often while being paid by their employer to do so. As soon as the contract is signed and the art delivered, you will not hear from them again until they want something. Being ghosted by clients is normal. It's nothing to be offended by, but it is frustrating to want information about your designs but never get answers. It's important to keep your perspective in these situations. Know the difference between a client wanting your art and a person wanting to be friends. They are not the same thing. Business transactions are not friendships. Keep in mind that while your work is often your life, their job ends when they go home and negotiating deals with you is just what they do when they are at work.
To help with the frustrations, before you deliver your art, ask all the questions you may not get answers to when they have what they want. Don't fear asking questions because you think that will make them take their business elsewhere. You need to know when to expect payment, how your art will be used, and what to expect. If they can't answer your questions, that is a sign you should not ignore.