Laptop Trouble

My laptop was handed in for repairs, not even yet 6 months old, on 3rd January 2015. After 2 months I went to the branch weekly to find out whats happening. They then refer me to the Call Center which informs me that they are doing a motherboard replacement. I'm promised a new laptop, but after 2 more months and loads of calls from my side to Call Center I receive my laptop back. Which I would gladly have taken if it worked. When I turn it on it has no memory or Windows or anything on it. Service report says it is repaired. I want to terminate the contract because it is breach of contract from their side, according to the branch I'm going to be penalized? Whatever happened to the consumers rights?