Hi,
If you need to update your exit date with your old employer, first reach out to their HR team or someone who can help. You can also contact EPFO for assistance or file a gravedance. Another option is to look at your last payslip from them. If you were paid for a full month, you can use the last day of that month as your exit date. Just make sure the date you give is correct. It's a bit risky, but it might be your best bet if nothing else works.