Xiaomi India — issue with the purchased mobile

I purchased redmi note 5 pro which is in warranty. I am facing problems in my phone like battery issue, hotspot not working properly, hanging problem, problem in installation of applications from play store. Have visited xiaomi's service centre thrice. First time they had done something in my phone. When second time i reached to them they doesn't provided me new jobsheet and mentioned bounce case in the previous jobsheet and returned my phone after sometime. When third i contacted them they told me that my phone is water damage. If my this was the issue they must have told me this thing in first time. But my issue is not resolved. I'm still facing the same problem. Kindly help me.