Make your settlement offer, and futher add that they agree not to report to the CRAs if paid within time X.
That will then become a contract limitation that is legally binding, and provide you legal remedy should they report.
Call them and see if they will go lower and make a payment right then. If it has to do with paydays and payment. It would be worth it to go USPS next day delivery to get a collections off your report. Good Luck!