IPHONE 7 - PROBLEM WITH SPEAKER AT THE RECEIVER END

HI, I AM UNABLE TO HEAR ON MY I-PHONE 7 NOR THE RECEIVER IS ABLE TO HEAR ANYTHING.

I visited the Service centre in HSR Bangalore and they clearly say the phone has a manufacturing defect and they asked me to Pay Rs. 1500 to write a report.

Please can someone guide on the process if its a manufacturing defect.

Regards

Vijay