Harrasment By Apple Service

I am Iphone 13 pro Max user. Recently I got issue with my phone as my phone display was going off again and again. As its in warranty I showed this to Authorised center and they submited my phone. Next day they called me and informed that issue has been solved as it was software issue.

Next day I collected my phone but the issue was still there and I went back to them to submit it again. They told me that now they feel its a hardware issue so it will send to Apple main center. I agreed.

Few days passed and then I enquired about the status and they told main department told to observe the phone before sending.

I then called apple support regarding this. The person told me that from now onwards he will take care of this and will find solution for this. But still many days passed and then one day he told me to collect the phone from service center unrepaired and then apple will guide me what to do next.

I did that. Every day that apple person called me and asked me to setting changes from restore to all other settings. Nothing worked. Many days passed doing this everyday.

I told that guy that look we tried everything related to software. Now definetly its a hardware issue. He says i agree but we as apple are not able to decide what is the solution for this. I told I have submitted many videos and even apple technician has marked the problem. Its your responsibility to find the solution. I am ready to again submit my phone. Repair or replace.

But unfortunately they are not responding so now what should I do?