I'm a newbie! I have searched the threads and found similar probs, but nothing that helped. I got a windows phone and wanted to access my calendar so changed all my appointments in my ipad calendar to my email account calendar (listed under calendars on the calendar page), and all seemed fine. i colour coordinated it all and everything was there. It didn't feed back to my email calendar on my phone, so I went into settings and started to fiddle. BIG MISTAKE. Now, none of the appointments i changed are there. At first even the calendar disappeared, although it has come back now but without the data.
Any ideas? I'm not backed up anywhere as my computer refused to recognise my ipad, a problem i should have addressed earlier...