Poor Service

On Friday the 7th August 2015, I went into the dealership to purchase a Fan belt for a Nissan 1400 bakkie, the guy in the service department took for ever to attend to me, finally when he did assist and had supp**** me with the part I required, I had left only to find out the part was incorrect went I arrived home. Never the less I went back to the dealership to return the part. The guy insists that it is the correct part when clearly it was not. He then phones \I don't no who