Help! 616 handsfree frozen up...

[Blowpipe]

Hope someone can help me out! I've got a Nokia 616 handsfree kit wired into the car.

I noticed that it wouldn't connect with my phone as it usually does, and that the unit wouldn't switch off when the car is shut down. I went through the menu, eventually finishing up trying with 'Restore factory settings'. At this point it froze up for good.

How can I get the unit back to it's reliable self? Thanks!