At my wits end with NIMBLE

How does a collection company "outsource" one's account but still update credit bureaus with non-payment status? It's been 6 months of me trying to settle my account but am not getting any help from Nimble or the alleged outsourced company but every month Nimble tarnishes my credit profile. To make matters worse, even the "outsourced" company cannot locate my account. Nimble agents give me incorrect telephone numbers or redirect me to a number that is not in service. How do I get assistance please I want to settle this account?