Low earpiece volume in Iphone XR(3 months old device)

I have already visited the apple authorized service center twice( in MUMBAI, INDIA-400013), but came back disappointed. They ran diagnostics test and said that yes the earpiece volume was low but then after they cleaned with some solvents the sound level became audible but still far from the normal iPhone earpiece sound( which is loud). Now I can talk to someone at home but when I step outside and walking on the roads then it becomes hard for me to hear what the other person is saying. This is really frustrating as the service center declined by service saying that my device now has passed the hardware diagnostics so they cant help. Also I have been in contact with Apple customer support team and my case is already being handled(or was handled :( , by a senior technical representative( His name was Arjit). He had said that he will handle case personally until I am satisfied with the device. The most ironical thing is that prior to him I have been told the same by 2 other Apple representatives( I will attach the email threads sent from them). Its a shame that Apple service in India has fallen to such a miserable level !! This is completely unacceptable from Apple who claims to keep user satisfaction as number one priority.

I am copy-pasting( because I don't seem to find any document attachment option) the complete mail thread below which I sent to apple India customer support. All I got from them is a robot generated mail saying that contact customer care via call or visit the service center. I have done both and now sitting disappointed, this seems to be my last resort, please tell what should do get my iPhone XR working properly again.

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