Who is to blame for such poor service by the Department of Home Affairs

I am very disappointed with the service provided by the DAH. My critical s****s visa application was rejected. Reason being, they believe my current visa had expired already when I made the application of which my current visa is valid at present. Someone must be accountable for this because the same department's agents confirmed that it was a mistake for the application to be rejected. Really disappointed because I have to pay more money to make an appeal.