Update Time:
We have more details now about the nature of the problem.
All site operations (betting, stats, etc) run through our API server. On the test platform, the API server barely uses any CPU; yet on the production platform it was running 100% despite the production platform being far more powerful. According to the processing stats we have, requests were being processed extremely quickly (~60ms/call avg) on the production platform. So something else is amiss. The major difference between the test platform and production, is that production has several additional security layers. It must be some dynamic within these layers that has introduced a bug not discovered on testing.
Long story short, there is a problem with the production API server (likely a problem with how the code is written, not the physical server itself). We have two excellent developers on this right now who are working as fast as possible to isolate the bug and resolve it.
Will post another update in several hours and assess an ETA then. Based on this ETA, we'll get user deposits returned. Thank you for your continued patience, we've had some really kind PMs and the community support is heartening