Hi to all,
i have problems with my Nokia N9 which i used perfectly for about 2,5 years. Suddenly since last month i detect more and more errors. My N9 was getting more and more laggy. It began with facebook app freezing when i tried to read a new message directly from the lock screen. then the camera app started not responding when started, followed by my phone counter app which doesen't count any more. Then some to-do entries got stuck on the feed screen and no matter what i tried to delete, change or move them to another date they always apeared on the feed with the old date like nothing happened. And now to the cherry of the cake - my battery got empty and when i switched the phone on again all my contacts and messages were gone - all! like they were deleted. I put some new conctacts again, but every time the phone switches off and on again they are gone. I had to delete and add my skype and facebook accounts so that they appear again in the contacts but all my telephone numbers are vanished. By doing this i realized that my e-mail accounts were also frozen and haven't fetched any new mails for more then a week. After deleting and setting them new now they work, and even appear on the list of new mails on the app screen (which dissapeared long time ago, but together with other minor bugs i took it for a normal phone behavior because we all know what the N9 is). On the plus side - the phone is not lagging that much anymore but of course about 500 phone numbers are gone.
Can you help me? You are my only hope! Is there a way to recover my contacts and messages again? Strangely when i connect the N9 with PC i see some contact cards which i got per sms but they don't get imported

And you didn't use any sync service (google contacts, ms live?) for backing up your contacts?

Are you kidding?
Never ever. That was one of the reasons not switching to N9 (not having possibility to sync on PC)! But go with the cloud ...

About OP problem: looks like you are doomed. N9 is known for loosing contacts and/or messages from time to time!
You might search the forum for solution tries (there are lots of threads/posts/tries) but I doubt there is a real 'solution'.
Furthermore check the files
/home/user/.contacts/tracker
/home/user/.cache/tracker/meta.db
after copying to PC for any hints (manual work to do).