Hi. Sorry for the expressed delay.
[In case you are not able to hear the caller]
This will normally happen due to a bad ear piece or ear speaker. In which case you will have to have your headset dissembled and the ear-piece replaced. On some occasions, the ear piece may fail to function due to a short on the headset's. This can often be corrected by having the device's PCB using an electronics cleaner.
[In case you are not able to be heard by the caller]
This is 9/10 instances caused a clogged microphone hole. This is a small pin-hole sized and you can in the same way unclog it using a pin or needle. In extreme occasions, the microphone in the insight may have sadly failed. In which case again you will have to have your headset dissembled and the microphone replaced.
Please kindly comment below for any further necessary assistance