New court documents reveal a heated exchange between Ms. Spears’s lawyers and the former business manager of her estate.New court documents reveal a heated exchange between Ms. Spears’s lawyers and the former business manager of her estate.Read MoreSpears, Britney, Suits and Litigation (Civil), Tri Star Sports & Entertainment Group, Spears, Jamie (1952- ), Rosengart, Mathew S, Greenhill, Robin