Passport — grant of passport facilities

Hi,

I had submitted my passport and all the required documents on 29th dec 2009 to get a ECNR. My file number is: m029979. Today I have recieved a communication letter which doesnt not specify what the passport office is looking for. The text of the letter says:

With reference to your application/letter dt 29th dec 2009 on sub cited above and to request to furnish the desired information/documents within 15 days failing which your case will be treated as closed.

your passport is being returned without service/closed

Furnish your reply along with the above mentioned reference number.

actually i have applied for ECNR status, and i got my passport back with ecnr stamp. and today i received this letter. if they close my case, will my passport become invalid?