It sounds like you’ve taken the appropriate steps to seek care at Mayo Clinic.
Unfortunately Mayo Clinic receives more requests for appointments than available openings. Mayo's physician experts have likely reviewed your case with their colleagues. Their review led them to determine that Mayo Clinic cannot offer further treatment for you at this time. It is the goal to provide the best care each patient needs, however Mayo does not want you to incur additional costs for evaluation or travel if they do not feel they can offer care that is different from what you’re already receiving.

I know this is disappointing and hard to hear. Some members have reported that they've made an appointment request to another Mayo Clinic location and had success. Or they tried at a later date and been successful.