It happens sooner or later to all consulting designers: your client decides not to use your work or — if it’s what they hired you for — take your advice.
First of all, remind yourself that as a design professional you’re not taking anything personally. It might also help to remind yourself that contrary to a lot of narratives, it’s not your job to “make the client happy.” Rather it’s your job to solve your client’s problems as best you can. It’s your client’s prerogative to accept or reject your work. There may be a million reasons for a client not to adopt your solutions or take your advice. Whatever the reason, you cannot afford to take it personally.