A parent had a child who was suffering from leukemia. Several other parents in the same small town had children with leukemia or other diseases, and at least one other child had died. The parent hired an attorney in a mid-sized town twenty miles away because she believed that a chemical refinery in the small town was contaminating the groundwater. The parent called the attorney at least once a month for two years, but the lawyer has still not investigated the case. Only once during the two years did the parent actually speak to the attorney, and then all he said was, “These things take time.” The attorney could be subject to discipline for which of the following?