DMAT a/c updation of Bank A?C no

Dear friends,
I am having dmat account with Integrated enterprise for more than 5years.
My bank has migrated to Core Banking and hence there is change in account
no.
First I wrote a letter to DP informing them to update my account number as the bank had migrated to Core banking and hence everyone in that branch had change of account number from 4 digits to 11 digits. But DP did not accept the letter and asked me to fill up the form of change in bank account details. Along with that form they required me to submit a cancelled/or photocopy of the cheq showing new account number. Second they required Passbook's front page and last page showing new account number/or new statement from the bank showing new account number (the 11 digit stuff).
Now, as I have about 20 cheques balance in the passbook, bank would not issue me new cheque book but just strike out old a/c number and write new a/c number on the cheque leaves. Same with the passbook, they just stroke out old number and put the new number..hand written!!
I showed the DP what is my position, but they would.... stick to the rules.
To make matter simple I got a letter signed and stamped by the banker certifying that due to bank migrating to core banking my account number has changed from ..... (old no) to this.....(new no)..
but this was also not acceptable to DP!!!
Can some one throw some light about factual position as to what steps need to be taken.. is it not sufficient when bank certifies the old and new account number of a person???
Can you not have the passbook where postal address is different from your permanent address?? Can DP object to it that passbook address is different from the one registered with them?? (infact I haven't changed my address anytime.. passbook address carries office address and DP registered address is home address)..
what a hassle.. just because bank and RBI did something... and SEBI in its wisdom requires something else... just rigid rules!!!
Your guidance invited...

For change/modification in bankdetails on DP musst need Cancelled cheque (new a/c number showing)+copy of passbook/statement(new number).If a/c number overwritten on old number of passbook/cheque there need authorised signature of bank manager with bank seal.
This is my knowledge.try for guidence from other experience peoples of this forum.

The confirmation letter from the bank which states Old a/c number and New a/c number also serves the same purpose isn't it???

Dear Friend,

is your problem solved Now??.

finally which type of proof accepted by DP ("D"amit, "P"astered) people ??

I will come to know after 10 days... I have submitted bank's letter and waiting for their acceptance!!