If you are the "Curious" from 26 Jul and later posts and have been threatened several times that they are serving or filing papers against you in the next day or so and have not been served, then they are not going to be filed.  This almost certainly is a debt collector trying to scare you into paying a debt you do not owe or is too old for them to sue you about.

Here are links from the FTC website about debts and debt collectors that may prove helpful.

http://www.consumer.ftc.gov/articles/0149-debt-collection
http://www.consumer.ftc.gov/articles/0117-time-barred-debts