Nimble is always causing these unnecessary problems and have experienced the same issue with them before

It's been over 5 years my mother's name is still under judgement by this terrible collections department "nimble" ,if I hadn't check my mother's credit score on pulse she would have paid them money for nothing when she was blacklisted over the 5 years and account is now closed so why is nimble still running on her name . I need this issue sorted out asap or I will contact the relevant ombudsman.