wow thats a huge problem.the only option i know is to factory reset.
or i would recommend going to http://forum.xda-developers.com/galaxy-s3-mini and ask the same question.
Also i would recommend installing a custom rom it makes your device wayy faster.
this is a nice rom but voids your warranty
http://forum.xda-developers.com/galaxy-s3-mini/orig-development/rom-cyanogenmod-12-1-t3071937