Worst bank ever

Since I closed my account in July and never used it again it shows that they still deduct their monthly bank fees that will obviously be in arrears because I don't ban their any more they only reply saying that you owe us. How can I owe you money if I closed my account how many times must I inform you that I have closed my account before the new month nobody phoned me they just keep on putting interest and banking fees. They are the worst bank with the worst customer care.