Consumer Redressal

My name is Dr R K Mishra. I purchased new Sony audio system shake 66D from Dawar International Electronic PVT Ltd. Plaza Mall Gurgaon. After taking payment they said you go home and I will send you the product at your home. But when they send the SONY music system at my home all the speaker were in the cartoon without any foam and there were dust in the groove of woofer. There was no user manual and Warranty card inside the Box. Then i went next day to the dealer the same unit which was in the showroom display which I saw that day was not present. I said you sold me old product which was in your showroom. I said then where is your Demo set which was in your showroom. They said it is shifted to another showroom. Then I said why thee is dust and scratches on my music system and No guarantee card. I told them to replace my unit and give me guarantee card but they are refusing to do so. I send them email and called several time but they are not good person. Please help me. Dr R K Mishra