my speculation of what might happen is this: when battery is connected wrongly, all electrical & electronic devices will see the reverse voltage. electrical devices should less susceptible compared to electronics (e.g. bulbs & heating elements are electrical & not electronic). however, some electrical devices can be controlled by electronics. so the latter may fail instead of the former. when engine was started under reverse voltage condition, the alternator kicks in and take over the electric supply to the car. the alternator is connected in the correct way. hence everything that requires electric supply will see an instantaneous change in voltage direction. as power (P) = voltage (V) x current (I) and physics does not allow power to change instantaneously, any instantaneous drop in voltage is compensated by a corresponding instantaneous surge in current. fuses are typically located at the +ive terminal as there is where the current would normally flow. so they may not protect if the surge in current is at the -ive terminal. this instantaneous surge in current via the -ive connection might have caused damages to electronics. having said all these, i dont think that there is much of an option but to bring the car in to the agent and ask them to troubleshoot and isolate/identify the damaged components. good luck.