Go get your stuff the angst and heartburn are not worth the fight..
As far as the call/email situation that is the way of customer service today. If I were you I would use the email exclusively to communicate that way there is no misunderstanding..
If you want to be an A$$ report the rig stolen as it was taken without a proper authority. Did you give them POA in the end? If you did then disregard previous advice. Instead report them to your states insurance commissioner.
My guess is they are trying to figure out if you had a reason to torch the rig. They are probably looking at your finances to see if it may have been purposely set.