I am trying to figure out the best way to fix a drywall "issue" I have. I am partially redoing a closet. There was water damage to the upper half of the closet. The person I hired to help me fix it is a drywall specialist. The original closet is plaster. He told me if I took out the wall from the shelf support to the ceiling, including the ceiling, that he could drywall the top half and make it look like new. I ripped all that out but the shelf support and the lower half of the wall. He did his job, mostly. He left a gap between the plaster and the drywall that ranges from 1/2" to 1". Most of it runs right along the shelf support. I need to find a good way to fix this so I can still use the shelf. I have tried a few things but not much has worked. The person I hired was a friend, about every two to three months he leaves me a message to tell me he figured out how to make it right, when I call him back he never answers.