Poor Service coupled with substandard repair services

I took my iPhone 7 Plus for a battery replacement at the iStore on 1 Sandton Drive and when it came back the microphone wasn't working probably because people were complaining about the poor audio during calls. I took it back to the iStore and made them aware of this and one of the technicians in a very condescending way said that it's basically not their fault but they'd have a look at it anyway. I was called to collect it today and the issue still persists after they said everything is fine.