Paid up letter

I am in need of a paid up letter for an account that I paid up before 2012 acc number *** I'd: *** Been send all from A to Z for the last year Jet told me that they do not have me on they books any more I must call Nimble who told me that I'm not on their books coz I paid n closed the account before they took the books over my cel number is *** or *** . I phoned ITC and NCR for help n nobody can assist me . I received my credit report from TransUnion convincing me that the Debt Counselor is to assist me with the report. Please please please help me my Email ***