Asset Care - NCO Fin Paid an old debt--After almost a year still not off credit report. Why? Horsham Pennsylvania

I have been trying to clean up my credit for the 1-1.5 yrs. I have settled with most of the debtors. My credit report shows most of these as being settled or paid. I had a debt from a Wells Fargo credit card for somewhere around $2,000 they have been after me for years. I finally decided enough was enough and decided to be responsible. I settled with a company called NCO Financial through Asset Care for $1500. They were asking me for the balance of somewhere around $3,000 because of interest. I felt like it wasn't too bad of a deal because after all i had borrowed right around that amount in the first place. My credit report has never showed that account being settled or paid. I am having trouble getting a loan from anywhere with this thing on my credit. I have tried contacting them and i can never get through to a human being. Did i get totally screwed or is there a possibility that someone just hasn't done their job and reported it to the credit agencies. I don't know how it all works.
PLEASE HELP IF YOU CAN!!!!
Thanks,
Gus

Gus
Sandy, Utah
U.S.A.