From BPO Website FAQs :-
You are contacting me about a debt that I don’t believe is mine, what can I do?
Please call us on 0141 375 0958 so that we can resolve the matter.
Alternatively you can email us at firstname.lastname@example.org
or send us a letter to:
The Grange Business Centre
I think it was over 5 yrs since I was a proper BT customer until they revived my account to charge me £1.60 a month for an email account! and then insisted on sending me a paper bill after I declined it? Surely this would have taken a portion of the £1.60.
Debts can become statute barred.
It is non payment of a bill not borrowed money so debt may still stand.