failing security questions

Hi All, wonder if someone could help please?
UC claimant fails the security questions every time he/we contact UC. Claimant is adamant the answers are correct and the DWP noted the security questions down incorrectly. He made a phone claim for UC. He does have a very strong Bangladesh accent, and is quite hard to understand at times.
He says he originally made a claim in November 2020 but claim only started on 29.3.21. JCP, who will talk to us, said they have no evidence of a previous claim. UC, one helpful person who gave us some information even though claimant had failed the security questions, told us that the claim was ‘closed’ as a UC were unable to contact him, presumably for ID check and to agree claimant commitment.
As he fails the security questions I am unable to find any information on the previous claim or speak to his CM. I have contacted the partnership manager and am waiting a reply. Surely this is quite common, claimants forgetting the answers to the security questions? Is there any way to reset the security questions apart from making a new claim? Many thanks