African bank!!!!!

Had a loan with African Bank, had to go through the debt review process, and finished paying all my debt, INCLUDING AFRICAN BANK, received paid up letter from them, stating that the loan has been fully paid and outstanding balance is 0. Now a year later coming with stories that I owe them, threatened with legal action, calls and sms's daily from rude consultants. According to African Bank my account was under investigation and paid up letter sent by error, which is *******, loan was paid up fully, African Bank confirmed this and sent paid up letter!!!