speaker and microphone stopped working after I opened it

Both speaker and microphone stopped working after I opened it to replace the rear camera in my Note -4. When I call the phone, the vibrate mode works but it doesn’t ring. When I connect it using a bluetooth headset I am able to talk via whatsapp. But if I call the phone using the cellphone service, there is no audio even if I use the bluetooth headset. What is wrong? Could there be a loose connection with one of the connections or if something is to be replaced?