Hearing issues when making a call

[userxnl68BR52l]

Hello. I bought a refurbished Galaxy S10 plus last weekend. I transferred all the data from my S9, all seemed good, until I made a phone call. 

The other person was unable to hear my voice until I turned it to speakerphone. 

I can't find any issues with my apps, although I realise this may be the issue, but how do I even find out. 

Today I have factory reset the phone again, but still have the same problem.

Any help would be appreciated. Thank you Lisa 

[DanG92263]

Try turning off Bluetooth and trying the call again. I've occasionally had this occur when my phone is connected to a Bluetooth speaker.
Also, you may wish to check your settings to ensure media devices are to be played separately. Search 'Seperate app sound' in Settings.