Bluetooth music listening, please help

Hello. My car was 2012 model 3008. When I bought my car, a flyaudio e7521 type navigation device was installed by the authorized service. Bluetooth connection is activated during the conversation with the bluetooth in the vehicle or when a phone call is made, at this stage there is no problem. When the call ends, it switches to radio as if the connection is ending (connection does not end). I cannot listen to music in any way. I cannot transfer music from my phone to the device via bluetooth. I would like to express my gratitude to the precious forum members who can help with this.

You can see the user manual here. https://ekilavuz.com/flyaudio-e7521navi-navigasyonlu-oto-muzik-sistemi-oto-ses-ve-goruntu-sistemi--1458c22a9ca2de77-2