Faulty Lenovo Laptop

I bought a new Lenovo Flex 2 laptop on the 25th January 2015. Roughly 3 months of use, and the laptop started making terrible noises originating from the cpu fan. I took laptop back to Dion Wired Fourways on the 9th May. After 4 weeks in repair, I received the laptop back, with the promise that the laptop had been repaired. I began using it again, and started noticing a metallic buzzing sound, originating from the fan. On the 13th June, I returned to Dion Wired, explaining the situation, and again they booked the laptop into repair for another 4 weeks. Service report stated that they had cleaned out the CPU cooling system and app**** new heat paste. I again began working with the laptop and for the 3rd time, a metallic buzzing sound came from the under side and was worse when the laptop was moved in any way. I returned for a third time in July, this time wanting a refund, but none the less, it had to go in repair. And 4 weeks later they informed me that the laptop was ready for collection as there was \nothing wrong". I have started using it again and the noise is still present. There is obviously something wrong"