Apple India — my iphone 6 not working properly from last 3 to 4 months

Address: Mohali, Punjab, 140308

Website: APPLE

Hi team

From last 3 to 4 months my iphone 6 with serial no (Fdpv521uhxr5) not working well i am facing different different types of problems. Responding time of each app and each event is too slow some times phone get silent even on general mode, some time not able to pick call, some tome screen not visible screen becomes black, app crashes some times, some times beep voice hear at back end during using phone, typing respond time is more as compared to typing, overall more another problem occurs from last 3 to 4 months another thing service provide replaced my handset two times but the problems remains same no any solution get till now please help me too overcome from that problem. I am a big fan of apple phones from last 4 to 5 years but from last 4 to 5 months i am very disappointed by apple service please provide us solution.