Small company using SB server + exchange

I'm a new user/profile on exchange.

All working very well no issue bar one!

I have the default calendar as you would expect in Outlook but i also have
the "calendar in Mailbox - Mark Joseph" i.e. me!

These 'two' calendars do not syncronize I haven't had this before can anyone
help?

I would like that the default calendar was all I see and use and that when
appointments are sent to me and i accept or otherwise that these are then
inserted in the defuault calendar. this does not happen at present.

looking forward to your solutions!