You can find that information here:

https://steemd.com/@badfatcat

Once you have found the user that you delegated to, you can undelegate the amount delegated to them by using this link:

https://v2.steemconnect.com/sign/delegateVestingShares?delegator=YOURSTEEMITID&delegatee=IDYOUDELEGATEDTO&vesting_shares=0.000000%20VESTS

Be sure and change your steemit ID and their steemit ID in the link above (ALL LOWER CASE).