Service centre not able to solve the problem and managr making fool not accepting the fault

Respected sir/ madam
my name Bhima sankar

THAT FROM LAST 3 MONTHS I HAVE GOT 5 PROBLEMS IN THE MOBILE AND I HAVE KEPT MOBILE MORE THAN 1 MONTH IN THE SERVICE CENTRE .
WHAT SONY COMPANY WANT TO KEEP MY MOBILE ALWAYS IN THE SONY SERVICE CENTRE
2 TIMES CAMERA PROBLEM AND 2 TIMES TOUCH SCREEN PROBLEM
I HAVE NOT BUYED PHONE C4 TO KEEP IN SERVICE CENTRE

i have buyed my sony mobile c4 on 20th march 2016 in Rs 19000/-
my problem and trouble i m facing from this mobile and sony service centre
1] i got in problem in touch it was working automatically and not working properly, so i submitted that phone in sony centre they kept the phone for 15 days with no proper answer and how many days it will take , then after 15 days they called me to sony centre that phone is ready , when i check the phone then the same problem was occurring ,
then they told to keep the phone for 1 week again on same job sheet no , then also they were not able to short the problem in that 15 days , then
after 8 days phone was ok
but but
then next day there was problem in back camera, that image was blurr and not clear , when i called there and visited in sony service centre they told me we will change the camera in 1 weel
today i visited the sony service centre for the problem to change the camera ,
today when they changed the back camera the same problem is occuring , image is blurr and not clear .
when i showed them about the same problem they were not accepting the problem and defect , they were telling that sony has such type of camera and this is not a problem but again i showed them the demo after clicking pic they were not accepting , but after long discussion they accept the camera problem .
and they created they job sheet and kept my phone for 10 days .

again and again the same problem or new different different problem is occurring in sony c4 mb phone in last 3 months .
and in this 3 month the phone was in the sony service centre for 1 month
i have buyed the phone of 19000 for my use not for to keep the phone in service centre ,
i m tired of the phone always occuring different differnt problem , in 3 months i have visited sony service centre for more then 6 times ,
always there is a problem and service centre is not able to repair that , and
they are not able to reply to the customer properly ,
they dont have the way to talk to the people
so my point is if i m facing problem again and again then i dont wish to keep that phone ,
so replace my phone with new one or give me in writing that this phone will not occur in future ..
bcoz i dont wish to keep in service centre i have buyed that for my use ,
due to many problem again and again i dont wish to use c4 mobile phone
,
At first time they told me that u will give benefit and the phone will b replaced but no they are telling we cant replace the phone
I request them due to many problem replace my phone but after 45 days they are telling not to replacemy phone
And in this c4 phone they have replace this phone to many customers and given new phone to customers then why not me

after many problem in 3 months they are not replacing this piece and not even they are able to solve the problem