Missing the last date for marks entry can be stressful, but there are potential steps you can take to resolve the issue:

1. **Contact the Institution**: Reach out to your school, college, or university administration immediately. They may have specific policies in place for late submissions or offer a grace period for genuine reasons. Explain your situation clearly and provide any relevant documents or proof of why you missed the deadline.

2. **Submit a Formal Request**: If your institution allows, submit a formal written request (via email or letter) explaining your circumstances. Be polite and professional, and if possible, include any supporting documents that show the reason for the delay.

3. **Look for an Appeal Option**: Some institutions may have an appeals process for missed deadlines. Check if your institution provides this option and follow the required procedures.

4. **Escalate if Necessary**: If the institution is unresponsive, consider escalating the matter to higher authorities like the academic head or registrar.

5. **Stay Updated**: Keep track of further updates or announcements regarding deadlines to avoid missing any future opportunities.

Taking quick and decisive action can increase the chances of a positive resolution.