Excel export does not export the data in the table just the name and table headings

I am trying to export a table of data extracted by Java, passed back to Ajax using JSON, and populating the table with Ajax in HTML. Using a table populated with data in the HTML works fine.

Java:

    if (packSummaryList == null || packSummaryList.isEmpty()) {
        response.sendError(HttpServletResponse.SC_BAD_REQUEST, "No one joined.");
    } else {
        String json = new Gson().toJson(packSummaryList);
        response.setContentType("application/json");
        response.setCharacterEncoding("UTF-8");
        response.getWriter().write(json);
    }

Ajax:

      .done(function(responseJson1a){
            dataType: "json";
    var tablebody = "";
    try{
          for (i=0; i < responseJson1a.length; i++) {
              tablebody += "<tr><td>"+responseJson1a[i].section+"</td><td>"+responseJson1a[i].metricTotal+"</td></tr>";
          }
          $("#mytablebody").empty();
          $("#mytablebody").append(tablebody);
    }
    catch(e){
    console.log(e);
    }
})

HTML:

    <div class="col-lg-3 col-md-3 col-sm-3 col-xs-3">
        <table class="table table-hover table-bordered" id="joinedTable">
            <thead>
                 <tr>
                    <th>Section</th>
                    <th>Joined</th>
                 </tr>
            </thead>
            <tbody id="mytablebody"></tbody>
        </table>
        <div style="text-align: center;">
            <span id="ajaxGetUserServletResponse1" style="color: red;"></span>
        </div>
     </div>