Consider me as a Customer calling to xyz company , " i am inquiring about my stuff has fixed or not, i don't know which dept. i should ask contact to

First of all before preventing the situation and finding out who to blame, we should get into the real issue of the customer and help solve it. Apologize to the customer about the situation and gain back the customers trust to the company. After resolving the customers issue then find out where the problem exist its not that we look someone to blame  but at least in this case we can prevent same thing happening in the future and make quality calls.