How to load data on datatable after update data to see last updated da

How to load data on datatable after update data to see last updated data using jquery ajax ?

I work on asp.net razor page .i i face issue i can't load data on

datatable using jquery ajax 

when load data for first time data table load data correctly

<table id="myDataTable" class="table" style="margin-top:20px;">
    <thead>
        <tr>
            <th>Company Name</th>
            <th>Branch Name</th>
            <th>User Name</th>
            <th>User Type</th>
            <th>Actions</th>
        </tr>
    </thead>
    <tbody>

        <tr>
            <td>@Model.MyData.CompanyName</td>
            <td>@Model.MyData.BranchName</td>
            <td>@Model.MyData.UserName</td>
            <td>@Model.MyData.UserType</td>
            <td>
                <button id="editDataBtn" style="width:100px;" class="btn btn-primary edit-btn" data-id="@Model.MyData.ID">Edit</button>
            </td>
        </tr>

    </tbody>
</table>

after update data i need to get updated data so i make as below :

            $("#updatedatabtn").click(function () {
                var userId = $("#userId").val();
                $.ajax({
                    url: '?handler=RefreshDataTable',
 
                    dataType: 'json',
                    data: { UserId: userId },
                    success: function (result) {
                        console.log(result);
                        $("#myDataTable tbody").empty();
                        $.each(result, function (index, item) {
                            $("#myDataTable tbody").append("<tr><td>" + item.CompanyName + "</td><td>" + item.BranchName + "</td><td>" + item.UserName + "</td> </tr>");
                        });
                    },
                    error: function (xhr, status, error) {
                        console.error("AJAX request failed: " + error);
                    }
                });
            });

public JsonResult OnGetRefreshDataTable(string UserId)
        {
            var result = userService.GetUserDetails(UserId.ToString());
            MyData = result.Result;
            return new JsonResult(MyData);

        }

but i get error 

expected result on datatable must be only one row because it display user details for only one user

error details