Nu Debt Management harrassing with emails

They keep sending threatening emails for an account that I don't even have. When i ask for a written signed document, they cant show that. So they say it's for telecommunications. But they cant present any evidence. Threatening to make my credit score bad. They are a worst company with people that lie. Why cant you just present evidence. All ****mers. Really. Very poor poor company. First do your research before harrassing people.