I rarely get my food the way I order it.

I have a heart condition and cannot eat salt or I will become breathless, and my heart will race. When I eat out, I always request something very basic such as an omelet with fruit and vegetable or a piece of fish and a vegetable. I check the menu before going to make sure they serve something I can eat. I always tell the server I have a medical condition, I cannot eat salt, and that I need everything "plain, no butter, no salt, plain", repeating myself 3 times. Three out 4 times the food arrives covered with butter and/or salt. I always enjoyed eating out and found it relaxing, and because I travel alot, it's a necessity. What can I do?