Samsung Washing Machine

We bought a top loader washing machine from Game Menlyn. Had it plugged in and started using and to our surprise for over four days the washing garments came out dirty. Took it back to game and they refused to take it sighting lack of knowledge on our part in using it. Samsung called us to say the type of detergent we use could be an issue. We don't agree with this reasoning cause its listed on the types of detergents to be used. They say if they send an agent to us it will be at our cost. Looking for help please.