India Post — my ignou's education documents delivered wrong address

Address:

New Delhi, Delhi, 110093

Sir/ma'am,
I had raised a grievance to ignou asking about the provisional degree and marksheet of my ignou course.
The reply i got from ignou was (Enclosed in attachment) that it had been sent on 18.03.2019 with registered post no. Rd[protected]in.

When i went to the indian post website to further investigate about my documents i found that my article was delivered on 20.03.2019.
But it actually not delivered home.

My complaint/grievance is that
1. Where are my precious educational documents?
2. What kind of service is it that even sensitive documents are not being taken cautiously?
3. I need my every document delivered at my home as soon as possible.
4. Strict action on the postman.?