Lack of response to money owed to me

Discovery Health just do not care about their clients. They are very quick to take your money but once they have made a mistake and admitted to owing you money back they cannot give you a date as to when they will be making the payment. I have phoned them twice to get this resolved, both time empty promises of " We will call you back" have been made with no response from them. When you ask to speak to a person in charge who can make a decision all you get told is they are not contactable.......How do you run a business like that? Who is ultimately responsible for making decisions? This is totally unacceptable customer service. I am disgusted by this total lack of respect that the client gets when they have agreed to pay me back for a mistake that they made and acknowledged.