well if you forgot the reference number it doesn't surprise me it's taking longer.
anyway from their website:
IMPORTANT: MISSING REFERENCE NUMBERS DELAY DEPOSITS
To speed up the process Bitstamp is kindly asking those who are missing a deposit to please contact our support and provide us with your name, exact amount that was sent and reference number or client ID.
Which I did 1minute after I sent the deposit, 7 business days ago.
They don't find a deposit while I gave them all the informations needed. They reviewed the case and looked for the deposit a few times already.
They are not answering on wether they have been hacked or not.