Any contribution hours you have recorded against volunteering tasks with one of Good2Give's volunteering partners (e.g. Communiteer) will be displayed on the My Giving History screen. You can access this screen from the My Giving History link in the My Giving tab.
Communiteer Volunteering Hours
If wish to modify the hours volunteered value, it can be changed via the Feedback tab within the volunteering project on Communiteer