Openreach has a system that ISPs can use to get tags cleared. Takes a few days from them requesting it. You need to escalate the issue with BT.
I wouldn't be surprised if when the number was previously used the broadband on it was never ceased when the line was. (It should be automatic).
My broadband basic info/help site - www.robertos.me.uk
| Domains,site and mail hosting - Tsohost
Connection - Plusnet
UnLim Fibre (FTTC). Sync ~ 59.4/14.4Mbps @ 600m. - BQM
"Where talent is a dwarf, self-esteem is a giant."
- Jean-Antoine Petit-Senn.
Allergy information: This post was manufactured in an environment where nuts are present. It may include traces of understatement, litotes and humour.