iPhone Apple refuse service on defective iPhone 7 Plus

So the iPhone 7 Plus have this issue where the microphone will stop working and you can no longer place or receive calls or FaceTime. This is a known issue with this iPhone and it has been the second time it has happened to me. The first time, under warranty, Apple replaced the phone, but now, it has been 3 years since the phone released and the Apple Care + has expired and Apple won't do a thing to help me. Do you guys have any suggestions on how to get my phone fixed?