My ip4 Bluetooth Enver ever Connects with other devices! Only successful connection was with the kia sportage car kit. Any idea?

My iPhone 4 never connects with any other devices using build-in Bluetooth but with kia sportage 2009 car kit! I tried iPhone, samsung s3, Sony xperia series ABD much more, all failed to connect. Living in Turkey but Apple here, looking interested only selling phones without giving support. I can't even send an email directly to apple. Help