Corrupted dwgs

Hi, We have been using Draftsight for over 2 years now and mostly its all been good. but unfortunately we have lost 82 dwgs for an entire project that has been ongoing for the last 6 months. We have a new project where a lot of the furniture drawn could have been copied and and reused, this how ever cannot happen now.

All the dwgs now show as being a BAK File only, I have tried many times now to recover these dwgs without any success, are there any other options I can try or is it a doomed venture.