Hello and welcome to
RTI India.
As you say that you booked the registered letter 3 yeard back and the registered list is kept only for 18 months in the post office, the information sought for you cannot be given to you under
RTI as the preservation period has already passed.
However the CPIO should have mentioned the reason as to why he cannot give the information. You can approach him again, and he might this time give you the proper reply
