Now Haloscan has restored the missing comments from March 13-14, but in the process lost the comments since. This is getting really frustrating. Here is what the Haloscan admins say:
Yes, we’ve noticed that a few user accounts didn’t sync properly with the new comments and I’m restoring them right this moment. Every comment will be restored within the next 4 hours.
I hope they restore them soon without losing anything.
UPDATE: It seems like all the missing comments have been restored.