HTC Corporation — The htc e9 plus mobile that i have purchased 8 months ago

Address:	Mumbai City, Maharashtra, 400057
Website:	NA

I had purchased a HTC E9+ 8 months back for almost 35 thousand, the phone is still in warranty but the phone does function well as all. It switches off on it own and restarts on its own.
I made a complain. I even gave the phone in the Service Center the did something and gave back in two day's time and then it worked for 2 weeks properly now it is not functioning properly again.
On calling their help center they are asking me to again go to service center i am working and it is a huge inconvenience for me to keep going again and again to their service center, plus they keep it closed on sundays when we are free. i demanded a handset replacement but they refused and asked me to submit the phone to the service center again.