PHP json数组删除JSON文件中的一行

Having a bit of an issue with some PHP code. I have an contacts list angular app to add and remove contacts. I have the add part done but the delete is giving me some grief. On ng-click I'm sending data with a $http request to remove a specific line in a JSON file. It's sending the data fine but I think something is wrong with my php...Having a bit of an issue with some PHP code. I