Using Fixed header , scrollY, responsive at the same time but fixed header not working ?

alka

I am using Fixed header , scrollY, responsive at the same time, but fixed header is not working. Code is as following.I know scrollY and fixedheader are not compatible. How can I solve this problem PLEASE HELP

 var table = $('#table_id').DataTable({
            retrieve: true,
            destroy: true,
            responsive: true,
            paging: false,
            scrollY: '68vh',
            "order": [],
            "oLanguage": {
                "sEmptyTable": "No Data available for this selection"
            },
            columnDefs: [{
                type: 'date',
                targets: [4]
            }, {
                type: 'date',
                targets: [5]
            }, ],
            dom: 'Bfrtip',
            buttons: [{
                extend: 'csvHtml5',
                text: '',
                titleAttr: 'Download CSV',
                extension: '.csv',
                filename: 'Time Tracking Report - with Session details',
                exportOptions: {
                    modifier: {
                        page: 'current'
                    }
                }
            }, {
                extend: 'pdfHtml5',
                text: '',
                titleAttr: 'Download PDF',
                alignment: 'center',
                bProcessing: true,
                footer: true,
                title: 'Time Tracking Report - with Session details',
                orientation: 'landscape',
                pageSize: 'LEGAL',
                message: 'Start Date:: ' + hidden_startdate_avail + ' - End Date:: ' + hidden_enddate_avail,
                pageSize: 'A4',
                exportOptions: {
                    modifier: {
                        page: 'current'
                    }
                }
            }],
            "footerCallback": function(row, data, start, end, display) {
                var api = this.api(),
                    data;

                // Remove the formatting to get integer data for summation
                var intVal = function(i) {
                    return typeof i === 'string' ?
                        i.replace(/[\$,]/g, '') * 1 :
                        typeof i === 'number' ?
                        i : 0;
                };

                // Total over all pages
                total = api
                    .column(6)
                    .data()
                    .reduce(function(first, second) {
                        var first = intVal(first) + intVal(second);
                        var first = first.toFixed(2);
                        return first;
                    }, 0);

                // Update footer
                $(api.column(6).footer()).html(+total);
            }
        });
        if (result == undefined) {
            console.log(" ");
        } else {
            new $.fn.dataTable.FixedHeader(table);            
        }