Contacts sync in the opposite direction I tried to sync my contacts in my phone (Android 4.0.3), and as a result all my contacts in my phone were changed to the old contacts I had in my google accont on the web. For example. if I had changed a phone number to a new one in my cellular phone before the sync, it changed back to the old number that was on the web.
Can I restore the up-to-date numbers that I lost? What could have gone wrong?
I remember having gone through the same problem years back (on a froyo device). Not sure what caused it, but I fixed it as follows:


Exporting ALL your google contacts to a file (make sure everything is in there)
Remove all contacts from google
Remove all contacts from phone
Import the contacts from the file (exported in (1)) to the PHONE
Sync the contacts
Verify whether the sync worked


After doing this two way sync worked perfectly for me. I can not guarantee that this will work for you, but it may be worth a try. Also, make very sure that the export in (1) is complete (check the contents of the file) - also, export to various file formats for safety.

Unfortunately, the changes you made on the phone will have been overwritten and I do not know of a way to revert that. In the future, if the problem persists, you can disable the sync and do it manually using files - it sucks, but at least you won't lose information.