The adapter provided with the 60s micro is intended only for some phones manufactured before 2011. If used with recent phones it may lead to poor sound quality or no sound at all. Thus please do not use the adapter.
Are you using a cover to protect your phone against damage? Some cases are rather thick or have an opening too small for the audio plug. This may prevent the Opis 60s micro plug from being pushed in all the way and consequently lead to audio problems due to poor electrical contact. You may easily test this theory by removing the case and test the handset again without it. You may also test the handset with another mobile phone. If the problem persists it the handset is very likely defective.