Speeduser7533 Why not just pair, restrict all the access, and then block it from the list of BT devices? This way it would be identified by the system anytime it tries to connect and be rejected.
The way I did it with my old car is simply change the device name. Not sure if it works in your case.
At last, if it really is a BT connection, then you would be able to use it only as a car speaker and play a recording asking to fix his gosh damn car ;)