WILL NOT REFUND DEFECTIVE ASUS PURCHASED

My wife purchased an Asus Laptop on the 14th October 2015. She tried to access Internet as she was prompted to install Office via Internet but was unsuccessful as it gave an error. She returned to the store the next day where they assessed the device and my wife was told by the sales person that he was going to remove the MS Office software and she must buy her own. We bought our own and loaded it only to discover that we had no Anti virus software. She took it back to the store and was told to purchase her own Anti Virus software which we did but it could not be loaded. We took the device back to the store and asked for a refunded which to this day is being refused. The solution as per the store manager is to book the device in for repairs upon which my wife had to pay and additional R400 for software to be loaded. This is disgraceful. We demand a refund....please help<br>