Claims not paid properly

I obtain authorization for my partners treatment of iv medication every month. This is approved under PMB for Hyperlipidemia and she must get this drip once a month and costs a fortune. Every month I follow Discovery's procedure and processes but every month I have to fight to get her treatment paid. I have been shut down by call center staff, shut down by team leaders, promised feedback, and yet I still get no response. Out of desperation I email their regional manager and even then get no response. What does one have to do to get things done the way they are supposed to be. I cannot go on being treated as if I'm an imbecile that expects the impossible. The attitudes of the staff are totally unacceptable. I have reference numbers, names and dates to proof my dissatisfaction with Discovery but still no-one takes me seriously. Because if they did, my issues would have been solved by now.