If you would like to change your artist or label account URL, head to the “edit profile” option in the menu. From there, you can update your URL in the “Bandcamp URL” field.
If your album URL has a “2” hanging around at the end, you can force the URL to update with some quick troubleshooting:
Rename the album to something else (changing a single character is fine)
Click "Update"
Rename it back to the original name
Click "Update" again
Otherwise, track URLs are pulled from the track titles, so if you'd like to edit the URL, you'll have to include any additions to the title as well. To get that edited, head to the track editor and update the track's title.