Faulty prduct

I purchased a HP laptop in May earlier this year. It gave problems after just 3 months. I took it back to to the store. The manager who assisted me said it would have to be sent away to be repaired. After na week he phones and tells me my laptop has been fixed and is ready for collection. Fetched it that same day. Worked fine when I tested it at home. The next morning it was faulty again. I decided to read through the fault report only to discover it belonged to a different customer. Back to the store once again. Since Saturday, 29 August, I have not received any feedback. I have made countless calls to the store and each time I get told they will phone me back. They never do. I find their service appalling to sau the least. The manager assured me they would repair or replace the laptop. Nothing has been done as yet.