Removal of debt review flag

Good day

I app**** for debt review in 2016 and later withdrew from it.I paid all my debt and the accounts were closed by my creditors. I noticed this year that the debt review flag still appears on my credit reports. I contacted Octogen but they requested me to get paid up letters for the accounts I had when applying for debt review Unfortunately I can't get those paidup letters as accounts are closed and they no longer exist on the system of creditors and the accounts no longer appear on my credit reports.

Kindly advise me what should I do to get my name removed from debt review as the process of getting paidup letters has failed.