Defective laptop

I am extremely upset with this company & their policies. I have bought a brand new 13” macbook and gave me difficulties within the first 3 days. Therefor, I went to the store and asked for an exchange as it clearly has a defect. They refused. A few days after I returned to the store as I encountered more technical problems. Again they said that they cannot exchange it, but will remove all the firmware etc. and put it back in again. They did it and I fetched it the following morning. That same weekend it gave me the same problem all over again, as well as new ones. I am going there today and see if they will give me a new one because this is unacceptable!!!