Flipkart - defective phone recieved

Recently I purchased a phone from Flipkart on ** August, which stopped working after * days. As per Flipkart policy I visited an authorised service centre in trichy on **th August and asked them to check the issue. They just did some software flush and informed us that the issue was resolved and promised that it won't happen again and confirmed there is no motherboard/hardware issue.

But the same issue occurred again on **th August. Note that all these happened within * days and again I visited the service centre today and asked them to check, they mentioned it's a software issue due to some app. Only God knows which app as I haven't installed any app other than whatsapp.

They started giving some rubbish explanations and detained to check the actual issue, which I'm not at all satisfied with.

As Flipkart mentioned (also checked with customer care) that I'm eligible to get the replacement item as it's just * days since I ordered the phone, and the same I have communicated to the technician and they just refused to provide a replacement.

Here are the problems :

When I first visited the Authorised service centre in trichy they just flushed the software without checking the actual problem. They have not created any job card and told me it's not required.

Are the technicians really qualified ?

They are not following the process nor fixing the problem.

The technician has no knowledge about the problem and how to explain that to the customer. He asked me to visit the service centre every time the problem occurs. It's not possible for me to leave my job and visit the service centre everyday to fix one or other issue