Your story of coming up from your mine and unintentionally getting banned has happened before, so I just wanted to do some extra checking to ensure no mistakes had been made. However, after some serious investigation I'm afraid that I can only conclude that this was intentional grief.
To start it off, this is an image of where you exited your mine compared to the place that you griefed
Secondly, while you were banned at 16:23:28 (see https://www.opticraft.net/bans/snowmanbuilder64
giving you 1.5 minutes to get your bearings on the surface, and in no way leaving you able to be "confused". There was no reason for you to break the wood except to intentionally grief.
Just in case I was wrong however, I also personally investigated the blocks below the house looking for a mineshaft. Needless to say, I found none.
If you think I've made any mistakes please feel free to correct me, but I'm fairly confident in my results.
For now, you'll remain banned.