I'm not sure what this means. I think it means that you still have the private keys for wallets in cold storage, but just don't have any account / trade data since the last backup. If that's the case, perhaps the right way to deal with this is:
(1) start with the last backup
(2) measure deposits / withdrawals since the last backup, based on blockchain data (surely you at least know the static addresses involved)
(3) apportion the net difference between accounts based on the verifiable deposits and withdrawals of each user since the last backup
Let's say for simplicity that there's 10 BTC in cold storage for all of Atomic Trade, and total deposits since last backup were another 10 BTC. If my user account balance 2 weeks ago was 1 BTC, and I deposited 1 BTC since then as verified on the blockchain record, I would receive a total adjusted balance of 2 BTC.
This really sucks though. I would expect to see a more active approach to M$. I'd be happy to help with a demand letter, etc. If you don't have any funds in cold storage offline, though, I would just say don't do anything crazy!
Z
Interesting idea the wallets are all fine they back up 3 times a day to an encrypted redundant storage system. I could probably write a script to reprocess all the wallet transactions but this wont account for the amounts traded and may make things worse... I will have to think about this one and how it would work and yes I am extremely unhappy with the way they are operating and the contempt show in there responses but that is probably no surprise what does surprise me is there complete and utter lack of responsibility since from my reading this has happened to many people. At least the private rack is already in place and awaiting the final software to bring the new site online.