<human>: So last December my wife had to take a trip to the emergency room here in Austin, TX.  I had been laid off that year and the benefits from my new job didn't kick in yet so we were at the time, un-insured.  Thank goodness it wasn't anything too serious, we were charged almost $900 for a 15 minute consult and $200 for a sonogram (which revealed nothing).  

  Anyway, we paid both of these bills and went about our lives as usual until 2 days ago when I got a notice from a collection agency that I apparently owe almost $3000 dollars for something related to this hospital visit a year ago.  I have already officially disputed the validity of the debt, but neither the collection agency nor apparently the hospital can tell me exactly what this debt was for or why I haven't heard anything about it until now.

Question is:  What in the hell could this charge even be for?  I know that you often get several bills for a single hospital visit but we already paid both the hospital and the 'specialist' and didn't receive any additional bills.  Anyone have any idea what the hell this could be for, we are kind of freaking out about this.

Can you provide a brief rundown of the text in within 3 sentences?
<bot>: got a mysterious $3000 bill for a year-old hospital visit that was paid in full at the time of the service, WTF?!