It seems to me thet althou the other person cancelled the claim either the insurance company or the other person has NOT notified the Police ,you really have nothing to worry about the other person is in the wrong a they drove off there is no way of telling who is responsible but the guilty party is usually the one who does not stick around .
The best thing is to either phone the station or better still call in to see a Police person and sort it out ,please try to calm down as you have done nothing wrong ,the other person is in the wrong as they drove off.I hope it is all sorted out the sooner the better the longer you leave it the worse your mind plays tricks with you .
Please post when it is sorted I wish you well.
In A Mo