Hello,

You might have it with you. You might have downloaded the file and have kept it somewhere. Look into that place or you might have got mail and there you might have that letter attached.

If they are not there then You may not get that letter now as those portals would be closed now as new batches has already started and there is no need of that webpage.

If you need it in urgent basis then you can write a mail to the board to send you the letter again to you mentioning why you need it and why you lost the copy which was given to you.

Hope it helps!