Xiaomi India — red mi note 4 4/64 gb to hang and not proper functioning

Address:

Bulandshahr, Uttar Pradesh, 431001

Sir my name is vinod. I having redmi note 4 handset which hang in frequently and if we attached a headset after we remove the headset symbol on screen long time due to that voice also didn't come.
Other problem is both keys volume n lock key didn't work properly in frequently.
And the service also is very bad...
This is second complaint regarding same problem but not any kind of response given to us... Please slove the problem..
As early as possible...