Bad service

My experience with FNB has been satisfactory at all. I purchased a smart device ( Laptop )from them. When the device came it wasn't working from the start, and so i spoke to the IT call centers to assist me. After all the factory settings reset it still wasn't working and seemed like the hard drive was crashed from the start. The FNB employee i spoke to told me i had 14 days to get a new device or cancel. Within those 14 days i cancelled my contract and sent the device back. Make note when i received the device, no documentation came with it telling me how many days i have to cancel or exchange etc. Then last week friday i received and email saying my cancellation fee is over R3000 and he computer was graded C. This means that the laptop is working in excellent condition. To me this is utter ******* as the laptop was not working 100%. Also they sent the contract policy saying i only had 7 days to cancel the contract, when one of they own employees told me i had 14 days. Whose fault is that ? This means that i cant be held liable for incorrect communication on FNB side.I tried calling all the numbers to sort this issue out, and every time i get referred to another department only to get referred to again. No body wants to assist me and get this issue resolved. I have wasted precious time and money trying to sort my contract out only to be in the same position... I would like to cancel this whole contact without paying the huge amount. I mean they sent me a broken laptop and expect me to be happy... Please can you assist me in getting this resolved.