Awaiting refund for +- 6 months

I have been calling the Sars contact centre for months for a refund that is due to me. Every time when I call, they will tell me I have to wait 21 days. When I call back and ask for progress, then there is something wrong again. They don't even call you when they need information to finalise your query, they are waiting for you to call back. Last month they said the query is with there accounts department and the refund is in progress, today when I called, they told me they need a letter from my bank. I feel that the consultants working SARS is ***********. I am really disgusted with the service that I received from them.