Frustrated by Nible Group

I don't understand why I have Nible Group on my credit record, I have do not have any contract with them and never ever spoke to anyone from that so called company, till I was advised that they could be collecting on my prescribed (over 8 years debt with finchoice)is it even legal to collect on prescribed debts, what must I do for this mother sucker's to remove themselves from my credit bereu record, I now can't do ****.