What now?

Has anyone ever been in default with ace cash express? i went in default with them in august and the check was sent to corp/ office. I have paid a couple of time on the amount, as much as possible. They are telling me now if it is not paid by the end of sept. the would take me to court. Can they take me to court if I am truley trying to pay them? I live in AZ. Would the have to serve me papers at work or home? not real sure what the process is? Thanks for your help/