iPhone 11 noise microphone

I have iPhone 11. Is second one with noise static microphone. I bought in November 2019 iPhone 11 64gb after three days screen change colour. I got to apple store and they told we did compare and told me some iPhone are different than usual we sale. Doing!! I did return it to original store and got new one the same model. May 2020 my iPhone 11 have noise microphone nobody could hear me. Apple replaced with new one. Now on December 2020 I have same problem againI contact apple and told me your phone has no warranty anymore it was for three months on replacement phone even on original I had left 6 months warranty apple gave me 90 days. And to fix the mic right now they told me around 500$ something. Apple is stealing people.