Swing BT phone connection help

Can anyone help?  Swing radio in a 2014 Yeti.

Problem: Cannot hear other person when receiving call thru BT.

I've been able to connect the phone via BT. It recongnises the phones, contact etc all imported.

When receiving a call, the phone rings thru the system, the MFD displays the callers name, I press the phone button on steering wheel but can't hear them. However the caller is able to hear me via the car's microphone.

If the radio is on, it doesn't mute and switch to caller, ( switch to BT ) it just continues to play radio. BT is unavailable when pressing mode.

If however I play music on the phone, it comes thru the car speakers via BT no problem.

Have tried both Samsung S23 and A51 with exactly the same results.

Any idea what the issue is ?   I've only been  told it used to work OK, but I haven't seen it working properly so that may be a red herring.

Cheers.