Do it over (Score 1)

If you were in a court of law, would you be able to testify exactly when and where this happened, and particularly what was said by whom? You may wish to give them another chance to say it, by calling a meeting with the perpetrator and taking explicit written notes, beginning with "I'd like to understand the details behind the statement you made on X date about extending my employment beyond the three weeks' notice I've given in my memo". If they're unwilling to repeat this, it will reveal that they are in fact harassing you, and they know it. Then immediately get your personnel records copied, and after that have a discussion with HR. Be prepared to be escorted out that day. You can always contact your State Labor Department for advice, and employing a lawyer to write a memo is a good idea, especially after you're gone. Recording a conversation without telling someone puts you into a bad legal position in court (although it seems fun, and I've done it).