Bluetooth issues

i I have an iPhone C and my vehicle is a 2012 Toyota Rav 4. My Bluetooth goes through the radio. when using Siri, my Bluetooth freezes in the talking mode. I can get back to my home screen on the phone but I cannot get back to radio mode or turn off the car radio. The only way I can reset it is to make a manual phone call or **** off my car. It's incredibly annoying and inconvenient. Anyone else have this problem? If so how did you fix it?!