BTC 480 Not Stereo

I have my iPhone connected via bluetooth to the Kino BTC 480 and the audio comes only from the left side of the car, I tried to connect my old iPhone SE via 3.5mm cable directly to the car and is working fine, also the I use the iPhone on the other car with bluetooth from stock I can hear everything in stereo without any issue… also I received the BTC 480 as a present so I do not have the receipt from Amazon…