Some advice please.

[stupified]

What is the name of your state? Nevada
My ex has filed with the courts a motion to get me to pay back medical bills.
She is trying to get me to pay bills that I have never seen from 1992-present. I belive that this was brought up because I filed a motion to terminate C/S. Which was granted by the judge to stop when my daughter turned 18. Which she did a week after the court date. My ex has never sent me one bill whatsoever since our divorce in 91. I did recive 3 bills recently in which I payed in full. There has got to be some time frame for submitting medical bills to me for payment. Insurance companies require 30 to 90 day's to submitt bills to them for payment or they wont pay them. Should'nt that hold true for myself ? I have heard if the Latches defence Can I use this defence since I have been so unjustfully blindsided by this all of the sudden 13 years worth of medical bills? Somebody inlighten me on my rights please, I think it's just wrong.