Help! Speakers on both sides work but not together

[Fizzil92]

I was hoping someone could help me! I have an 08 Aygo with bluetooth. I wish I didn’t have the bluetooth as I never use it. But because of it I can only use one side of the Speakers at once. The bluetooth only uses and takes up the right side Speakers and the standard music player can only use the left side Speakers. Both sides do work but can only work with their respective device which is just annoying. Is this a known issue and does anyone know any way I can fix it so both sides work while playing music?