I have a long term part-time employee that has a hard time disconnecting after leaving the office or while on vacation. During our O3's I repeatedly find myself saying that I want him to get paid for the work he does, therefore, his work needs to be completed during his regular hours and he does not need to work beyond those hours. If the matter is urgent, I will call him directly, but there has not been one instance so far that I needed to do that. However, he keeps taking work home. He answers emails, makes phone calls, and drops and picks up work related material. I understand that previous management relied upon him after work (and he did not get paid) and this made him feel part of the team, and since I want to stop this practice, he feels like I am telling him he is not trustworthy and he is not important to our organization. For example, I asked for a minor correction on a work event he was heading and he voiced concern over not getting paid for the event. I told him he should put the time down on his timecard and he became upset that I wasn't "getting it." I repeated: you get paid for the work you do. 

He says that he cannot keep up with his workload unless he is brought on full time, which we are not able to do. I have offered to extend his hours certain days and give him long weekends (while still operating within his part time approved work hours), reassign some of his work temporarily until he can get caught up, assist him with the tasks that are falling through the cracks, etc. He has declined all of my offers because he does not want work "taken" from him and he thinks that he can still get the tasks done. Unfortunately, he has a lot of errors in his work and the tasks are not getting completed correctly. 

My concern is that he cannot get his current workload completed in his work day. I have not been giving him new tasks to complete and he is still overwhelmed, even though I think that he should be able to complete them with better time management. He continously takes work home and does not want to get paid for doing it. I'm at a loss. I have never had an employee want to work for free so much. But, I want him to get paid for the work he does. What can I do?