Try this one:
And this one also if you are on steam:Requires Windows 7:
1) Navigate to Users> Your User Folder > My Documents > My Games > Borderlands 2 > Willowgame > SaveData > (Number) >
2) Right click profile.bin and select Restore Previous Versions
3) Select the most recent previous version and click restore
4) Do the same for the Save000x.sav file for your character. The x is the number of character in order of creation. So, if it was your first character created, restore SAve0001.sav
In Steam Right click BL2 > Properties > Local Files > Verify integrity of game cache
Do this as many times as it takes to reset. Took 3 for me. Read someone took 15 tries.
Did you edit your file to get more Gold keys? Replace with original file before doing this.
Have fun.