Horrible service affecting my credit profile

Nimble opened a collection account against my name on an account that was settled several months prior and closed. My credit profile shows that I have 7 missed payments with Nimble group and this is not correct. The account in my name with Nimble is closed and I don't know why they still haven't rectified that I did not miss payments with them because my account that they were collecting was already closed when they wanted to collect.