Xiaomi India — Sound problem and working process very slow

Address:

Buldhana, Maharashtra, 444303

Sir 2 days before sound problem start in my handset automaticaly...means sound automaticaly very low thats why i have not listening song or video...second problem is mobile process is very slow...
I had contact to xiaomy customer care center bt they r not receive the cl...
...and in my native place xiaomy cervice center not available...
My handset : mi4i (i had purchase mobile 5 - 6 month before)
So please solve my problem as early as possible...