Samsung A900 for Sprint

I have a Samsung A900 phone from Sprint. It syncs up fine and works well, except for the fact that I constantly receive 'Unsupported Calls'. These are calls that are not coming from my phone but for whatever reason my car is ringing. I cannot answer these calls, only hit disconnect repeatedly tell the ringing stops. This mainly happens in busy areas so I'm assuming I'm picking up signals from other cars/phones. I have gone to Sprint and have received the most rescent upgrades to the software but still have problems. The ghost calls are a hassle because once they start the ringing will start again within 5-10 seconds of disconnecting the previous ringing until I get to a less populated area. It doesn't always happen in the same spot and some days are worse then others.
UPDATE -
I called Sprint. The tech guy said that they are not working on a fix for this problem (I hope he's wrong). He says it sounds like the Prius Bluetooth is in 'Discovarable Mode' or 'Pairing Mode'. He said that these 'Unsupported Calls' are actually the Bluetooth picking up signals from other bluetooths or phones. He suggested that I contact Toyota and ask if there is a code I can punch in to turn off the 'Discovarable Mode' or 'Pairing Mode'.
Anybody know who I should call? I am going to search for the number & will let you know what I find out.