BUG

After updating minecraft on my mac I logged into the game and started playing. The game was getting slower and lagged a lot so I logged out of the game. When I reopened the previously selected world, all I see is my hole town that I took countless of hours and days to build divided into pieces and randomly misplaced. I tried to log out and then to log in again but nothing changed. I wish to contact minecraft's support team to get the problem solved and be able to play again in the same world, unfortunately  I couldn't find their email as I was always transferred to the help and support page with no link or email address in it.