I would consider consulting an attorney and inform him/her of the incident so you can start a record in case abuse and harrassment should follow. If you are approached again let them know that you have consulted an attorney and they need to refer ALL future inquiries to that attorney. They will either have to present what they have or back off completely. And of course, the foregoing is my personal opinion and not legal advice (all except for the part about contacting a bone fide lawyer, that is!).