If it is a cheap cabinet you can use a hammer and screwdriver or other bar and just pound the lock into the cabinet till you only have a hole.
Or if you want to continue to use the cabinet without the lock. You can drill it out.
Or you can call a lock smith and they will open and repair.
If the cabinet were open you could just replace the lock from the back side.
Greg
Webmaster
Winter Park Homes for Sale