They can put it in your credit report but it has to be listed as a "collection account." In other words, you may have a listing for Sam's Club and the collection agency but anybody evaluating your credit would understand it's the same debt. If you pay it, it will be listed as paid but the record remains in the credit file for 7 years, the legal limit.
You have the legal right to see what the agencies are reporting and contest what's in the report if you disagree with it's accuracy. The credit agencies are required to publish your side of the story also so anyone evaluating your credit gets to see both sides of the issue.
