Paid up account still showing as open after 3 and a half months

I paid up this account back in October 2024 through their solicitors. I sent them the paid up letter from the solicitors and have been calling every week to get this updated and closed with the credit bureau. I once called in December and was advised the manager is away it’s her birthday and this will be actioned in 3 days time when she returns. Still today the account is showing as open. I called again 1st week of January they said they’ll escalate this and close the account and send me the paid up letter to send to transunion still nothing!!! I’m beyond livid at this point. I’ve never seen such incompetence