Claims

I have been calling and talking to numerous call agents nothing gets done. They say they will call back and rarely do. I paid cash for my operation LAST YEAR and discovery doesn't want to pay me back. I call and they always have an excuse. They tell me it's done and everything is sorted out. But nothing. I call again and there is now new problems. How do I get help? I'm so frustrated. I can't keep on calling. I can't keep on explaining the entire story to someone new who won't end up helping.