Panashea

Gotta get a new one): You can either report it stolen to Microsoft and get a coupon for Minecraft, buy new one if customer service sucks, or goodbye forever. 

email microsoft, it's quite hard to get but you'll have to give some ips and some info away but it can be done via support

and im sure once you get an account you will be able to contact admins and tech and recover your inventory from your old accounts personas, same with locked chests though that would require an admin afaik