I discovered earlier today that I’d left the lid on my vault freezer wide open for a week, the contents ( fish, chicken, broccoli) was amazingly frozen solid. Is there any chance that it is okay or is it possible that it has been thawing out and refreezing off and on over those 6 or 7 days?
Assuming that it’s one of those where the lid is on the top, then that style of freezer (a.k.a. “coffin freezer” or “chest freezer”) is pretty good at holding cold air in and keeping things frozen, because cold air settles to the bottom. Grocery stores use open-top display freezers, and they are able to still keep things frozen.
I would suspect that, so long as everything in there still seems to be frozen, it’s very likely been frozen the whole while.
If the food defrosted at all with the lid open, then freezer didn’t have the power to keep it frozen, If the freezer didn’t have the power to keep it frozen then it doesn’t have the power to refreeze them with the lid open. Since everything was frozen then it most likely was always frozen. However if there was wind that may not apply.
Freeze partly filled bottles of water upright then lay them down in the freezer. if you do this again, you can tell if anything thawed then re-froze.
I found that the stuff at the top was soft. I know that I can take stuff out of the bottom and put in on the table, and it takes 2 days to thaw even like that, so I wasn’t worried about the hard stuff below the top 6 inches.
Everything should be fine. We’ll check your posting activity for the next few days just in case. 
On the bright side, you have done your bit to slow down global warming this week.
I realise that’s a joke, but the opposite is kind of true; the freezer compressor was probably running constantly to try to keep the contents frozen.