problem with Backup file, Need to restore contacts topic

I was trying to update my A90s to a new OS (though couldn't succeed ). But now the problem is that i am unable to restore it via backup restore. It start restoring the device but at the end it gives the following error
Error: Write Error
Error: Invalid header magic
i dont want anything else just i want to restore my contacts that were on phone!!!
i think there might be a problem with "userdata.backup" file. but as far as i remember backup was successful
Backup was made via Android System Recover <3e> in CWMR