Cheating by LG service centre

Dear friends,I am located at Vashi , Navi Mumbai. Last month my LG washing machine went out of order. I lodged a complain at their toll free number. Technician from LGs service centre in Sanpada, Navi Mumbai, came next day and replaced a so called defective part. Since the packing of this part was damaged, I wanted to check the Company price vis a vis price actually charged. To my shock, the Asst Service Manager told me that the technician has fixed a spurious part purchased from local market. He purchased this part for Rs 800 and has inadvertently charged me Rs 950(as per receipt given). Earlier in 2007, when I was located in Prabha Devi, Mumbai, in a similar case, the LG technician charged Rs 750 towards the cost of a spare. By mistake, he left the packing material of the spare at my home. Later on from the bar code of LG on it, I could make out that the actual Company price of the part was only Rs 250 or so. After complains to LG and follow up, the service centre refunded me the excess charged and gave a revised receipt.In 2007 they were only over charging. In 2012 now they are fixing spurious parts also.I am following up with LG. Pl help me in creating pressure on LG so that my grievance is redressed and LG is prevented from cheating others.sadan sinha