Does Nedbank know how to write a paid up letter

My husband past away 3 years ago. For the last 2 and a half years we have been trying to get a paid up letter, but it seem to be to much of an effort to do so. The account is in a credit.... so you owe me money. The estate lawyer have asked for the letter and you send the accounts. If it will make you as an entity richer keep the money...... can I just please have the paid up letter.