haha, don't ever call a girl a chick...

first of all, don't ever call a girl a chick, it just like calling a black negro...

now, who actually send you this letter? most likely, she just blowing smoke, but still you need to careful.

you should also call your liability insurance, file an incident report, in case there going to be a full blown law suite...

when you reply, just stand firm on "you didn't say it"...its very difficult to prove a "he said/she said" case.