This error has become popular as many Oppo customers are facing this issue these days. We hope Oppo will look into the matter and fix it in near future. In the meantime allow me to provide you alternate ways to find your phone and to back-up information from the device.
Here are the alternate ways:
1.) Find phone function: Kindly go to 'Settings' > Safety and privacy > Tap on Device administrator > Enable the 'Android Device Manager' > Go to the link: www.google.com/android/devicemanager to use the function.
2.) Back-up information: Kindly use the 'Backup and restore' application to backup your data.
Source - http://community.oppo.com/en/forum.php?mod=viewthread&tid=42905
You have also mentioned that you have lost your contacts and other data from your Oppo phone. So, in order to restore data from Oppo phone check out this - http://www.androiddata-recovery.com/blog/how-to-recover-deletedlost-data-from-android-oppo-phone
I hope it will work for you.