Lenovo — lenovo vibe k4 note multiple issues

I had purchased lenovo vibe k4 note last year on december. After a week it started hanging and restarting. With other issues like heating and network loss. I had visited the nearest service centre but they're unable to fix the issue. They had no answer for it. Please help. I had very excited to buy this set. But all it gives me is unsatisfaction and disappointment.