Keep phoning about outstanding bills that are paid

My father paid everything he owed and closed his account at Edgars. Regularly he still gets messages and phone calls he must pay up. Many times he told them he paid all outstanding money and closed his account. This really is frustrating. They also threat him with leagal actions. EDGARS even take the card a year ago when he close the account. I cant believe that is the treatment Edgars give our pensioners.