Is this how a collection agency works ?????

[lhut]

I have perfect credit, yesterday I ran a credit check and it showed a black mark on my rating from a county ambulance ride to the ER back in 2006. It was an over sight on my part, I thought the bill had been paid and have not recieved any phone calls or mailings to lead me to believe otherwise. I contacted the collection agency and I'm happy to go pay it off but I was told they would not be taking the black mark off my credit rating even if the debt was paid in full. Now I'm just ticked off. Doesn't seem like they offer people much motivation for paying a debt off. Is this legal and standard procedure ?