they just dont want to close my account and it running up i owe them over R400

i have told them to close my account how many times i have received letter as well i have went to tygervalley branch an yet they dont want to close my bank account they tell me i have to keep paying in i refused and my bank account is now R423.00 and the interest is going hire .i refused to pay i dont ever use my account the last i used it was last year ..the consultants at tyger valley branch nedbank are to pathetic, how is it that i have to pay in so much money and i dont us the account , i refuse to pay in.