Lenovo Service

I am furious and disappointed by the service I have been getting. My laptop is 6 months old and it gave problems from the start. I took it into the store I bought it from and they tried reloading windows after 2 days it still gave issues. We sent it to Lenovo as under warranty and first, they wanted me to pay for my warranty. How does that even work! In the end, they said they would reload the Firmware because that is what is causing my laptop to keep on restarting for no reason. Then they had a problem and said they have to reload the windows instead after the worker told them reloading windows doesn't work. Then they said it's fine they will fix it after 3 weeks of waiting for my urgently bought laptop. I felt like they are just playing around, first, they wanted money for under-warranty and then they have many excuses and then they take 3 weeks. I recently got the laptop back and they did nothing to fix it, it is still giving the same problem as before. :( I can't with this. I need this laptop for work. I can't do anything on it then it restarts every 10 minutes. I bought this laptop with the intention that It will work. Not having problems!!!!! Now I have to take it in again for you guys to fix it this is not right!!!!!!!!!!!!