This could be a very bad thing for your credit! You want to write to the credit agencies again, stating that this is an incorrect entry. By paying the creditor, especially if you didn't owe it, will pretty much guarantee that you'll have a "late pay" note on your credit report for the next 7 years, starting at the date the creditor reports the payment. If you don't owe it, you need to write to all three agencies, and dispute it.
Credit companies WANT to remove "dings" you don't deserve. They can be sued huge amounts of money if they're wrong and you can show you've disputed it.
Mark
thanks. I will try again based on you and justlurking’s info.
hopefully it’s not going to take 3-6 months to resolve.