Credit intel harassment

This company keep on mailing me regarding an outstanding debt that I know nothing about. They are threatening me with court action and being 'handed over'. It is difficult to get hold of them, but on the 2 occasions which I did, I asked them for details of the so-called outstanding debt. I was promised emails with the details but nothing was forthcoming. I also emailed them with all the past correspondence to their emails, with no response. There is zero response to any communication, except the constant emails that says I owe money, which is not the case.

I'm extremely agitated and feel like seeing a lawyer to get them to stop harassing me, but do not want to spend money on something that I do not owe for in the first place.

This company is useless and harasses people.