HDFC Bank — Misplaced the Registry document and no answer on it

I had opt home loan from HDFC . I have registry in 2011 and now my load is full paid . On document release they are dining that they don't have registry document. I did complain and not getting any response.

below is complain copy :

I went to collect document to Vaishali Branch as document was arrived as per my request . HDFC Representative told me Registry paper is missing in set of document folder and this is not with HDFC and I have to get this from Builder “Mahagun” . After long argument, HDFC Representative has agreed that HDFC will collect registry paper from builder and will call me to collect paper

Now This is very serious matter, In case if builder will not have registry paper, who will be responsible for it. As I have home loan, last 10 year paid all the amount with interest and HDFC is not bother about the main document. I have few question and want answer on it.
1. Who was responsible to collect registry paper at time of registry ? I paid amount for this service
2. Why was this not audited in last 10 years ?
3. Now a days many builder are bank corrupt and offices are closed, In this case customer document will get misplaced, then who will take this responsibility ? this is very serious matter.
4. Is this a value to customer, who paid all EMI without any failure and in blind trust that registry document is safe with Bank ?
5. Is this a moral value and right approach to ask customer go an find you registry paper yourself.

One last thing I am not going to ignore this and I want my all document to be hand over to me in this week without any failure. I was planning to get other home loan but if this is case I will never go with HDFC Home Load and will do the same for my all reference. This is very careless and irresponsible behavior from such a leading bank.

Please let me know in next 24 hours.

Account Number –[protected]